Difference between revisions of "API:EPrints/Database"

Latest revision as of 21:20, 4 March 2022

EPrints 3 Reference: Directory Structure - Metadata Fields - Repository Configuration - XML Config Files - XML Export Format - EPrints data structure - Core API - Data Objects

API: Core API

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NAME

EPrints::Database - a connection to the SQL database for an eprints session.

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DESCRIPTION

EPrints Database Access Module

Provides access to the backend database. All database access done via this module, in the hope that the backend can be replaced as easily as possible.

In most use-cases it should not be necessary to use the database module directly. Instead you should use EPrints::DataSet or EPrints::MetaField accessor methods to access objects and field values respectively.

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Cross-database Support

Any use of SQL statements must use quote_identifier to quote database tables and columns and quote_value to quote values. The only exception to this are the EPrints::Database::* modules which provide database-driver specific extensions.

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Quoting SQL Values

By convention variables that contain already quoted values are prefixed with Q_ so they can be easily recognised when used in string interpolation:

my $Q_value = $db->quote_value( "Hello, World!" );
$db->do("SELECT $Q_value");

Where possible you should avoid quoting values yourself, instead use a method that accepts unquoted values which will (safely) do the work for you.

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CONSTANTS

All the SQL_ column types defined by Perl module DBI and the following:

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SQL_NULL

A column value is undefined.

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SQL_NOT_NULL

A column value is defined.

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INSTANCE VARIABLES

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$self->{session}

The EPrints::Session which is associated with this database connection.

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$self->{debug}

If true then SQL is logged.

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$self->{dbh}

The handle on the actual database connection.

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METHODS

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Database

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new

$db = EPrints::Database->new( $repo, [ %opts ] )

Create a connection to the database.

Options:

 db_connect - Boolean. Also connect to the database (default: true).

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create

$db = $db->create( $username, $password )

Create and connect to a new database using user account $username and $password.

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build_connection_string

$dbstr = EPrints::Database::build_connection_string( %params )

Build the string to use to connect to the database via DBI.

Parameters:

dbname - Database name (REQUIRED).
dbdriver - Database driver (e.g. mysql, Oracle, pgsql, default: mysql).
dbhost - Database host.  Assumes localhost if unset.
dbport - Port to connect to database host.  Assumes default for driver if unset.
dbsock - Socket file to connect to database through.

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connect

$db->connect()

Connects to the database.

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disconnect

$db->disconnect()

Disconnects from the EPrints database. Should always be done before any script exits.

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set_debug

$db->set_debug( $boolean )

Set the SQL debug mode to true or false.

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set_version

$db->set_version( $versionid );

Set the version id table in the SQL database to the given versionid (used by the upgrade script).

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get_version

$version = $db->get_version

Returns the current database schema version.

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is_latest_version

$boolean = $db->is_latest_version

Return true if the SQL tables are in the correct configuration for this edition of eprints. Otherwise, false.

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get_server_version

$version = $db->get_server_version

Return the database server version.

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get_default_charset

$charset = $db->get_default_charset

Return the character set to use.

Returns undef if character sets are unsupported.

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get_default_collation

$collation = $db->get_default_collation( $lang )

Return the collation to use for language $lang.

Returns undef if collation is unsupported.

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get_driver_name

$driver = $db->get_driver_name

Return the database driver name.

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error

$errstr = $db->error()

Return a string describing the last SQL error.

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retry_error

$boolean = $db->retry_error()

Returns a boolean for whether the database error is a retry error.

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duplicate_error

$boolean = $db->duplicate_error()

Returns a boolean for whether the database error is a duplicate error.

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begin

$db->begin()

Begin a transaction.

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commit

$db->commit()

Commit the previously begun transaction.

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rollback

$db->rollback()

Rollback the partially completed transaction.

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type_info

$type_info = $db->type_info( $data_type )

See DBI/type_info.

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get_column_type

$real_type = $db->get_column_type( $name, $data_type, $not_null, [ $length, $scale, %opts ] )

Returns a SQL column definition for $name of type $type, usually something like:

 $name $type($length,$scale) [ NOT NULL ]

If $not_null is true column will be set to NOT NULL.

$length and $scale control the maximum lengths of character or decimal types (see below).

Other options available to refine the column definition:

 langid - character set/collation to use
 sorted - whether this column will be used to order by

langid is mapped to real database values by the "dblanguages" configuration option. The database may not be able to order the request column type in which case, if sorted is true, the database may use a substitute column type.

$data_type is the SQL type. The types are constants defined by this module, to import them use:

 use EPrints::Database qw( :sql_types );

Supported types (n = requires $length argument):

Character data: SQL_VARCHAR(n), SQL_LONGVARCHAR, SQL_CLOB.

Binary data: SQL_VARBINARY(n), SQL_LONGVARBINARY.

Integer data: SQL_TINYINT, SQL_SMALLINT, SQL_INTEGER, SQL_BIGINT.

Floating-point data: SQL_REAL, SQL_DOUBLE.

Time data: SQL_DATE, SQL_TIME.

The actual column types used will be database-specific.

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Basic SQL Operations

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do

$success = $db->do( $sql )

Execute the given $sql.

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prepare

$sth = $db->prepare( $sql )

Prepare the given $sql and return a handle on it.

Use the execute method on the returned DBI handle to execute the SQL:

 my $sth = $db->prepare_select( "SELECT 'Hello, World'" );
 $sth->execute;

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prepare_select

$sth = $db->prepare_select( $sql, [ %options ] )

Prepare a SELECT statement $sql and return a handle to it. After preparing a statement use execute() to execute it.

Returns a DBI statement handle.

The LIMIT SQL keyword is not universally supported, to specify this use the limit option.

Options:

 limit - limit the number of rows returned
 offset - return limit number of rows after offset

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execute

$success = $db->execute( $sth, $sql )

Execute the SQL prepared earlier in the $sth. $sql is only required for debugging purposes.

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update

$success = $db->update( $dataset, $data, $changed )

Updates a EPrints::DataObj from $dataset with the given $data. The primary key field (e.g. eprintid) value must be included.

Updates the ordervalues if the $dataset is ordered.

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_update

$rows = $db->_update( $tablename, $keycols, $keyvals, $columns, @values )

Updates $columns in $tablename with @values where $keycols equals $keyvals and returns the number of rows affected.

N.B. If no rows are affected, the result is still true, see DBI's execute() method.

This is an internal method.

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insert

$success = $db->insert( $table, $columns, @values )

Inserts @values into the table $table. If $columns is defined it will be used as a list of columns to insert into. @values is a list of arrays containing values to insert. These will be quoted before insertion.

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insert_quoted

$success = $db->insert_quoted( $table, $columns, @qvalues )

Inserts values into the table $table. If $columns is defined it will be used as a list of columns to insert into. @qvalues is a list of arrays containing values to insert. These will NOT be quoted before insertion - care must be exercised!

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delete_from

$success = $db->delete_from( $table, $columns, @values )

Perform a SQL DELETE FROM $table using $columns to build a where clause. @values is a list of array references of values in the same order as $columns.

If you want to clear a table completely use clear_table().

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count_table

$n = $db->count_table( $tablename )

Return the number of rows in the specified SQL table with $tablename.

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clear_table

$db->clear_table( $tablename )

Clears all records from the given table with $tablename. Use with caution!

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Quoting

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prep_int

$mungedvalue = EPrints::Database::prep_int( $value )

Escape numerical $value for an SQL statement. undef becomes NULL. Anything else becomes a number (zero if needed).

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prep_value

$mungedvalue = EPrints::Database::prep_value( $value )

Escape $value for an SQL statement. Modify value such that " becomes \" and \ becomes \\ and ' becomes \'.

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prep_like_value

$mungedvalue = EPrints::Database::prep_like_value( $value )

Escape $value for an SQL LIKE clause. In addition to ' " and \ also escapes % and _.

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quote_value

$str = $db->quote_value( $value )

Return a quoted version of $value. To quote a LIKE value you should use:

$db->quote_value( EPrints::Database::prep_like_value( $foo ) . '%' );

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quote_int

$str = $db->quote_int( $value )

Return a quoted integer for $value.

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quote_binary

$str = $db->quote_binary( $bytes )

Some databases (Oracle/PostgreSQL) require transforms of binary data to work correctly.

This method should be called on data $bytes containing null bytes or back-slashes before being passed on quote_value.

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quote_ordervalue

$str = $db->quote_ordervalue( $field, $value )

Some databases (Oracle) can't order by CLOBs so need special treatment when creating the ordervalues tables. This method allows any fixing-up required for string data $value for $field before it's inserted.

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quote_identifier

$str = $db->quote_identifier( @parts )

Quote a database identifier (e.g. table names). Multiple @parts will be joined by dots (.).

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prepare_regexp

$sql = $db->prepare_regexp( $col, $value )

The syntax used for regular expressions varies across databases. This method takes two quoted string and returns a SQL expression that will apply the quoted regexp $value to the quoted column $col.

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sql_as

$sql = $db->sql_AS()

Returns the syntactic glue to use when aliasing. SQL 92 databases will happily use AS but some databases (Oracle) will not accept it.

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sql_like

$sql = $db->sql_LIKE()

Returns the syntactic glue to use when making a case-insensitive LIKE. PostgreSQL requires ILIKE while everything else uses LIKE and the column collation.

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Counters

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counter_current

$n = $db->counter_current( $counter )

Return the value of the previous counter_next on $counter.

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counter_next

$n = $db->counter_next( $counter )

Return the next unused value for the named $counter. Returns undef if the $counter doesn't exist.

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counter_minimum

$db->counter_minimum( $counter, $value )

Ensure that the $counter is set no lower than $value. This is used when importing eprints which may not be in scrict sequence.

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counter_reset

$db->counter_reset( $counter )

Reset the $counter. Use with caution.

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next_doc_pos

$n = $db->next_doc_pos( $eprintid )

Return the next unused document position for the given $eprintid.

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Dataset Data

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exists

$boolean = $db->exists( $dataset, $id )

Return true if there exists an EPrints::DataObj from the $dataset with its primary key set to $id. Otherwise, return false.

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add_record

$success = $db->add_record( $dataset, $data )

Add the given $data as a new record in the given $dataset. $data is a reference to a hash containing values structured for a record in the that $dataset.

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remove

$success = $db->remove( $dataset, $id )

Attempts to remove the EPrints::DataObj with the primary key $id from the specified $dataset.

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Searching, caching and object retrieval

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cache_exp

$searchexp = $db->cache_exp( $cacheid )

Return the serialised search of a the cached search with $cacheid. Return undef if the $cacheid is invalid or expired.

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cache

$cacheid = $db->cache( $searchexp, $dataset, $srctable, [$order], [$list] )

Create a cache of the specified search expression from the SQL table $srctable.

If $order is set then the cache is ordered by the specified fields. For example -year/title orders by year (descending). Records with the same year are ordered by title.

If $srctable is set to LIST then order is ignored and the list of IDs is taken from the array reference $list.

If $srctable is set to ALL every matching record from $dataset is added to the cache, optionally ordered by $order.

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cache_table

$tablename = $db->cache_table( $id )

Return the name of the SQL table used to store the cache with $id.

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cache_userid

$userid = $db->cache_userid( $id )

Returns the userid associated with the cache with $id if that cache exists.

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get_cachemap

$cachemap = $db->get_cachemap( $id )

Return the cachemap with $<id>.

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search

$ids = $db->search( $keyfield, $tables, $conditions, [ $main_table_alias ] )

Return a reference to an array of $keyfield IDs - the results of the search specified by $conditions across the tables specified in the $tables hash where keys are tables aliases and values are table names.

If no $main_table_alias is specified then M is assumed.

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drop_cache

$db->drop_cache( $id )

Remove the cached search with the given $id.

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from_cache

$items = $db->from_cache( $dataset, $cacheid, [ $offset, $count, $justids ] )

Return a reference to an array containing all the items from the given $dataset that have IDs in the cache specified by $cacheid. The cache may be specified either by ID or serialised search expression.

$offset is an offset from the start of the cache and $count is the number of records to return.

If $justids is true then it returns just a reference to an array of the record IDs and not the objects themselves.

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drop_orphan_cache_tables

$c = $db->drop_orphan_cache_tables

Drop tables called cacheXXX where XXX is an integer. Returns the number of cache tables dropped.

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get_single

$obj = $db->get_single( $dataset, $id )

Return a single <EPrints::DataObj> from the given $dataset with primary key set to $id.

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get_all

$items = $db->get_all( $dataset )

Returns a reference to an array with all the <EPrints::DataObj>s from the given $dataset.

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get_cache_ids

@ids = $db->get_cache_ids( $dataset, $cachemap, $offset, $count )

Returns a list of $count IDs from $cache_id starting at $offset and in the order in the $cachemap.

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get_dataobjs

@dataobjs = $db->get_dataobjs( $dataset, [ $id, $id, ... ] )

Retrieves the records in $dataset with the given $id(s). If an $id doesn't exist in the database it will be ignored.

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get_values

$values = $db->get_values( $field, $dataset )

Return a reference to an array of all the distinct values of the EPrints::MetaField $field for the $dataset specified.

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sort_values

$values = $db->sort_values( $field, $values, [ $langid ] )

Sorts and returns the list of $values using the database.

$field is used to get the order value for each value. $langid (or $session->get_langid if unset) is used to determine the database collation to use when sorting the resulting order values.

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get_ids_by_field_values

$ids = $db->get_ids_by_field_values( $field, $dataset, [ %opts ] )

Return a reference to a hash table where the keys are specified $datasets's $field value IDs and the values are references to arrays of IDs.

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dequeue_events

@events = $db->dequeue_events( $n )

Attempt to dequeue upto $n events. May return between 0 and $n events depending on parallel processes and how many events are remaining in the queue.

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ci_lookup

$value = $db->ci_lookup( $field, $value )

This is a hacky method to support case-insensitive lookup for usernames, emails, etc. It returns the actual case-sensitive version of $value if there is a case-insensitive match for the $field.

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Password Validation and Secret Fields

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valid_login

$db->valid_login( $username, $password )

Returns whether the clear-text $password matches the stored crypted password for the $username.

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secret_matches

$db->secret_matches( $dataobj, $fieldname, $token [, $callback ] )

Returns whether the clear-text $token matches the stored crypted field with $fieldname for the $dataobj according to the $callback function.

If not set, $callback defaults to EPrints::Utils#crypt_equals.

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is_secret_set

$boolean = $db->is_secret_set( $dataobj, $fieldname )

Returns a boolean for whether the secret $fieldname for $dataobj has a value set.

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Database Schema Manipulation

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has_sequence

$boolean = $db->has_sequence( $name )

Returns true if a sequence of the given $name exists in the database. Otherwise, returns false.

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create_sequence

$success = $db->create_sequence( $name )

Creates a new sequence object with $name and initialises to zero.

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drop_sequence

$success = $db->drop_sequence( $name )

Deletes a sequence object with $name.

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has_column

$boolean = $db->has_column( $table, $column )

Return true if the named $table has the named $column in the database.

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drop_column

$success = $db->drop_column( $table, $column )

Drops the named $column from the named $table.

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get_primary_key

@columns = $db->get_primary_key( $tablename )

Returns a list of column names that comprise the primary key for the $tablename.

Returns an empty list if no primary key exists.

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index_name

$name = $db->index_name( $table, @cols )

Returns the name of the first index that starts with named columns @cols in the named $table.

Returns undef if no index exists.

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get_index_ids

$ids = $db->get_index_ids( $table, $condition )

Return a reference to an array of the distinct primary keys from the named SQL $table which match the specified $condition.

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create_index

$success = $db->create_index( $table, @columns )

Creates an index over @columns for named $table. Returns true on success, false otherwise.

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create_unique_index

$success = $db->create_unique_index( $tablename, @columns )

Creates a unique index over @columns for named $table. Returns true on success, false otherwise.

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create_foreign_key

$ok = $db->create_foreign_key( $main_table, $table, $key_field )

Create a foreign key relationship between named $main_table and named $table using $key_field.

This will cause records in $table to be deleted if the equivalent record is deleted from $main_table.

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get_tables

@tables = $db->get_tables( [ $dbname ] )

Returns a list of all the tables in the database.

$dbname specifies a particular database name of current connection has access to more than one database.

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has_table

$boolean = $db->has_table( $tablename )

Returns boolean dependent on whether a table of the $tablename exists in the database.

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create_table

$success = $db->create_table( $tablename, $setkey, @fields );

Creates a new table with $tablename based on @fields.

The first $setkey number of fields are used for its primary key.

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drop_table

$db->drop_table( @tables )

Delete the named @tables. Use with caution!

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rename_table

$db->rename_table( $table_from, $table_to )

Renames the table named $table_from to $table_to.

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swap_table

$db->swap_table( $table_a, $table_b )

Renames table named $table_a to $table_b and vice-versa.

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EPrints Schema Manipulation

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create_archive_tables

$success = $db->create_archive_tables()

Create all the SQL tables for all datasets.

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drop_archive_tables

$db->drop_archive_tables()

Destroy all tables used by EPrints in the database.

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create_version_table

$db->create_version_table

Make the version table (and set the only value to be the current version of EPrints).

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drop_version_table

$db->drop_version_table

Drop the version table.

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has_dataset

$db->has_dataset( $dataset )

Returns true if $dataset exists in the database and has all expected tables including ordervalues and index tables.

This does not check that all fields are configured - see </has_field>.

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has_dataset_index_tables

$db->has_dataset_index_tables( $dataset )

Returns true if index tables for $dataset exists of if this is not indexable.

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create_dataset_tables

$success = $db->create_dataset_tables( $dataset )

Creates all the SQL tables for the specified $dataset.

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drop_dataset_tables

$db->drop_dataset_tables( $dataset )

Drops all the SQL tables for the specified $dataset.

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create_dataset_index_tables

$success = $db->create_dataset_index_tables( $dataset )

Creates all the index tables for the specified $dataset.

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create_dataset_ordervalues_tables

$success = $db->create_dataset_ordervalues_tables( $dataset )

Creates all the ordervalues tables for the specified $dataset.

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has_field

$db->has_field( $dataset, $field )

Returns true if $field is in the database for $dataset.

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add_field

$db->add_field( $dataset, $field, [ $force ] )

Add $field to $dataset's tables.

If $force is true modify/replace an existing column. Use with care!

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remove_field

$db->remove_field( $dataset, $field )

Remove $field from $dataset's tables.

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rename_field

$ok = $db->rename_field( $dataset, $field, $old_name )

Rename the $field in the $dataset from its $old_name.

Returns true if the $field is successfully renamed.

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create_counters

$success = $db->create_counters

Create the counters used to store the highest current ID of eprints, users, etc.

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has_counter

$success = $db->has_counter( $counter )

Returns true if $counter exists.

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create_counter

$success = $db->create_counter( $name )

Create and initialise to zero a new counter with $name.

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remove_counters

$success = $db->remove_counters

Destroy all counters.

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drop_counter

$success = $db->drop_counter( $name )

Destroy the counter named $name.

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User Messages

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save_user_message

$message = $db->save_user_message( $userid, $m_type, $dom_m_data )

Save user message provided in XML DOM object $dom_m_data as a sanitized string in a EPrints::DataObj::Message using $m_type to define the message type and $userid for the ID of the user whose message it is.

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get_user_messages

@messages = $db->get_user_messages( $userid, %opts )

Get the messages for a user with ID $userid and clear messages if $opt{clear} is set.

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clear_user_messages

$db->clear_user_messages( $userid )

Clear all messages for user with ID $userid.

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COPYRIGHT

EPrints 3.4 is supplied by EPrints Services.

http://www.eprints.org/eprints-3.4/

LICENSE

This file is part of EPrints 3.4 http://www.eprints.org/.

EPrints 3.4 and this file are released under the terms of the GNU Lesser General Public License version 3 as published by the Free Software Foundation unless otherwise stated.

EPrints 3.4 is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with EPrints 3.4. If not, see http://www.gnu.org/licenses/.

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@@ Line 1: / Line 1: @@
 <!-- Pod2Wiki=_preamble_
-This page has been automatically generated from the EPrints 3.2 source. Any wiki changes made between the 'Pod2Wiki=*' and 'Edit below this comment' comments will be lost.
+This page has been automatically generated from the EPrints 3.4 source. Any wiki changes made between the 'Pod2Wiki=*' and 'Edit below this comment' comments will be lost.
-  -->{{API}}{{Pod2Wiki}}{{API:Source|file=EPrints/Database.pm|package_name=EPrints::Database}}[[Category:API|DATABASE]][[Category:API:EPrints/Database|DATABASE]]<div><!-- Edit below this comment -->
+  -->{{API}}{{Pod2Wiki}}{{API:Source|file=EPrints/Database.pm|package_name=EPrints::Database}}[[Category:API|DATABASE]]<div><!-- Edit below this comment -->
@@ Line 21: / Line 21: @@
 Provides access to the backend database. All database access done via this module, in the hope that the backend can be replaced as easily as possible.
-The database object is created automatically when you start a new eprints session. To get a handle on it use:
+In most use-cases it should not be necessary to use the database  module directly. Instead you should use [[API:EPrints/DataSet|EPrints::DataSet]] or  [[API:EPrints/MetaField|EPrints::MetaField]] accessor methods to access objects and field  values respectively.
-$db = $session-&gt;get_database
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 34: / Line 32: @@
 <!-- Pod2Wiki=head_cross_database_support -->
 ===Cross-database Support===
-Any use of SQL must use quote_identifier to quote database tables and columns. The only exception to this are the Database::* modules which provide database-driver specific extensions.
+Any use of SQL statements must use [[API:EPrints/Database#quote_identifier|quote_identifier]] to quote  database tables and columns and quote_value to quote values. The only  exception to this are the EPrints::Database::* modules which provide  database-driver specific extensions.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_quoting_sql_values -->
+===Quoting SQL Values===
+By convention variables that contain already quoted values are  prefixed with <tt>Q_</tt> so they can be easily recognised when used in  string interpolation:
+ my $Q_value = $db-&gt;quote_value( "Hello, World!" );
+ $db-&gt;do("SELECT $Q_value");
+Where possible you should avoid quoting values yourself, instead use a  method that accepts unquoted values which will (safely) do the work  for you.
-Variables that are database quoted are prefixed with 'Q_'.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_constants -->
+==CONSTANTS==
+All the <tt>SQL_</tt> column types defined by Perl module {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}} and the  following:
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 45: / Line 68: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=head_methods -->
+<!-- Pod2Wiki=item_sql_null -->
-==METHODS==
+===SQL_NULL===
+A column value is undefined.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 54: / Line 80: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_build_connection_string -->
+<!-- Pod2Wiki=item_sql_not_null -->
-===build_connection_string===
+===SQL_NOT_NULL===
+A column value is defined.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $dbstr = EPrints::Database::build_connection_string( %params )
-Build the string to use to connect to the database via DBI. %params  must contain dbname, and may also contain dbport, dbhost and dbsock.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_instance_variables -->
+==INSTANCE VARIABLES==
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 67: / Line 101: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create -->
+<!-- Pod2Wiki=item_$self->{session} -->
-===create===
+===$self-&gt;{session}===
-  $db = $db-&gt;create( $username, $password )
+The [[API:EPrints/Session|EPrints::Session]] which is associated with this database  connection.
-Create and connect to a new database using super user account $username and $password.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 80: / Line 113: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_new -->
+<!-- Pod2Wiki=item_$self->{debug} -->
-===new===
+===$self-&gt;{debug}===
- $db = EPrints::Database-&gt;new( $session )
+If <tt>true</tt> then SQL is logged.
-Create a connection to the database.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 93: / Line 125: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_connect -->
+<!-- Pod2Wiki=item_$self->{dbh} -->
-===connect===
+===$self-&gt;{dbh}===
- $foo = $db-&gt;connect
+The handle on the actual database connection.
-Connects to the database.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 106: / Line 137: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_disconnect -->
+<!-- Pod2Wiki=head_methods -->
-===disconnect===
+==METHODS==
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $foo = $db-&gt;disconnect
-Disconnects from the EPrints database. Should always be done before any script exits.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_database -->
+===Database===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 119: / Line 155: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_error -->
+<!-- Pod2Wiki=item_new -->
-===error===
+====new====
+ $db = EPrints::Database-&gt;new( $repo, [ %opts ] )
+Create a connection to the database.
- $errstr = $db-&gt;error
+Options:
-Return a string describing the last SQL error.
+  db_connect - Boolean. Also connect to the database (default: true).
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 132: / Line 171: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_begin -->
+<!-- Pod2Wiki=item_create -->
-===begin===
+====create====
-  $db-&gt;begin
+  $db = $db-&gt;create( $username, $password )
-Begin a transaction.
+Create and connect to a new database using user account <tt>$username</tt>  and <tt>$password</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 145: / Line 184: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_commit -->
+<!-- Pod2Wiki=item_build_connection_string -->
-===commit===
+====build_connection_string====
+ $dbstr = EPrints::Database::build_connection_string( %params )
+Build the string to use to connect to the database via {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}}.
-  $db-&gt;commit
+Parameters:
-Commit the previous begun transaction.
+ dbname - Database name (REQUIRED).
+ dbdriver - Database driver (e.g. mysql, Oracle, pgsql, default: mysql).
+  dbhost - Database host.  Assumes localhost if unset.
+ dbport - Port to connect to database host.  Assumes default for driver if unset.
+ dbsock - Socket file to connect to database through.
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@@ Line 158: / Line 204: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_rollback -->
+<!-- Pod2Wiki=item_connect -->
-===rollback===
+====connect====
-  $db-&gt;rollback
+  $db-&gt;connect()
-Rollback the partially completed transaction.
+Connects to the database.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 171: / Line 217: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_archive_tables -->
+<!-- Pod2Wiki=item_disconnect -->
-===create_archive_tables===
+====disconnect====
-  $success = $db-&gt;create_archive_tables
+  $db-&gt;disconnect()
-Create all the SQL tables for each dataset.
+Disconnects from the EPrints database. Should always be done before  any script exits.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 184: / Line 230: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_archive_tables -->
+<!-- Pod2Wiki=item_set_debug -->
-===drop_archive_tables===
+====set_debug====
-  $db-&gt;drop_archive_tables()
+  $db-&gt;set_debug( $boolean )
-Destroy all tables used by eprints in the database.
+Set the SQL debug mode to <tt>true</tt> or <tt>false</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 197: / Line 243: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_dataset_tables -->
+<!-- Pod2Wiki=item_set_version -->
-===create_dataset_tables===
+====set_version====
-  $success = $db-&gt;create_dataset_tables( $dataset )
+  $db-&gt;set_version( $versionid );
-Create all the SQL tables for a single dataset.
+Set the version id table in the SQL database to the given <tt>versionid</tt> (used by the upgrade script).
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 210: / Line 256: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_dataset_tables -->
+<!-- Pod2Wiki=item_get_version -->
-===drop_dataset_tables===
+====get_version====
-  $db-&gt;drop_dataset_tables( $dataset )
+  $version = $db-&gt;get_version
-Drop all the SQL tables for a single dataset.
+Returns the current database schema version.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 223: / Line 269: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_dataset_index_tables -->
+<!-- Pod2Wiki=item_is_latest_version -->
-===create_dataset_index_tables===
+====is_latest_version====
-  $success = $db-&gt;create_dataset_index_tables( $dataset )
+  $boolean = $db-&gt;is_latest_version
-Create all the index tables for a single dataset.
+Return <tt>true</tt> if the SQL tables are in the correct configuration for this edition of eprints. Otherwise, <tt>false</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 236: / Line 282: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_dataset_ordervalues_tables -->
+<!-- Pod2Wiki=item_get_server_version -->
-===create_dataset_ordervalues_tables===
+====get_server_version====
-  $success = $db-&gt;create_dataset_ordervalues_tables( $dataset )
+  $version = $db-&gt;get_server_version
-Create all the ordervalues tables for a single dataset.
+Return the database server version.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 249: / Line 295: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_type_info -->
+<!-- Pod2Wiki=item_get_default_charset -->
-===type_info===
+====get_default_charset====
+ $charset = $db-&gt;get_default_charset
+Return the character set to use.
- $type_info = $db-&gt;type_info( DATA_TYPE )
+Returns <tt>undef</tt> if character sets are unsupported.
-See {{API:PodLink|file=DBI|package_name=DBI|section=type_info|text=DBI/type_info}}.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 262: / Line 310: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_column_type -->
+<!-- Pod2Wiki=item_get_default_collation -->
-===get_column_type===
+====get_default_collation====
-  $real_type = $db-&gt;get_column_type( NAME, TYPE, NOT_NULL, [ LENGTH/PRECISION ], [ SCALE ], %opts )
+  $collation = $db-&gt;get_default_collation( $lang )
-Returns a SQL column definition for NAME of type TYPE, usually something like:
+Return the collation to use for language <tt>$lang</tt>.
-  $name $type($length,$scale) [ NOT NULL ]
+Returns <tt>undef</tt> if collation is unsupported.
-If NOT_NULL is true column will be set "not null".
-LENGTH/PRECISION and SCALE control the maximum lengths of character or decimal types (see below).
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Other options available to refine the column definition:
-  langid - character set/collation to use
+<!-- Pod2Wiki= -->
-  sorted - whether this column will be used to order by
+</div>
+<!-- Pod2Wiki=item_get_driver_name -->
-'''langid''' is mapped to real database values by the "dblanguages" configuration option. The database may not be able to order the request column type in which case, if '''sorted''' is true, the database may use a substitute column type.
+====get_driver_name====
-TYPE is the SQL type. The types are constants defined by this module, to import them use:
+ $driver = $db-&gt;get_driver_name
+Return the database driver name.
-  use EPrints::Database qw( :sql_types );
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
-Supported types (n = requires LENGTH argument):
+<!-- Edit below this comment -->
-Character data: SQL_VARCHAR(n), SQL_LONGVARCHAR.
-Binary data: SQL_VARBINARY(n), SQL_LONGVARBINARY.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_error -->
+====error====
+ $errstr = $db-&gt;error()
+Return a string describing the last SQL error.
-Integer data: SQL_TINYINT, SQL_SMALLINT, SQL_INTEGER, SQL_BIGINT.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Floating-point data: SQL_REAL, SQL_DOUBLE.
-Time data: SQL_DATE, SQL_TIME.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_retry_error -->
+====retry_error====
-The actual column types used will be database-specific.
+ $boolean = $db-&gt;retry_error()
+Returns a boolean for whether the database error is a retry error.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 306: / Line 364: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_table -->
+<!-- Pod2Wiki=item_duplicate_error -->
-===create_table===
+====duplicate_error====
+ $boolean = $db-&gt;duplicate_error()
+Returns a boolean for whether the database error is a duplicate error.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $success = $db-&gt;create_table( $tablename, $dataset, $setkey, @fields );
-Create the tables used to store metadata for this dataset: the main table and any required for multiple or mulitlang fields.
-The first $setkey number of fields are used for a primary key.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_begin -->
+====begin====
+ $db-&gt;begin()
+Begin a transaction.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 321: / Line 390: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_sequence -->
+<!-- Pod2Wiki=item_commit -->
-===has_sequence===
+====commit====
+ $db-&gt;commit()
+Commit the previously begun transaction.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_rollback -->
+====rollback====
-  $boolean = $db-&gt;has_sequence( $name )
+  $db-&gt;rollback()
-Return true if a sequence of the given name exists in the database.
+Rollback the partially completed transaction.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 334: / Line 416: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_sequence -->
+<!-- Pod2Wiki=item_type_info -->
-===create_sequence===
+====type_info====
-  $success = $db-&gt;create_sequence( $seq_name )
+  $type_info = $db-&gt;type_info( $data_type )
-Creates a new sequence object initialised to zero.
+See {{API:PodLink|file=DBI|package_name=DBI|section=type_info|text=DBI/type_info}}.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 347: / Line 429: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_sequence -->
+<!-- Pod2Wiki=item_get_column_type -->
-===drop_sequence===
+====get_column_type====
+ $real_type = $db-&gt;get_column_type( $name, $data_type, $not_null, [ $length, $scale, %opts ] )
+Returns a SQL column definition for <tt>$name</tt> of type <tt>$type</tt>, usually something like:
+  $name $type($length,$scale) [ NOT NULL ]
+If <tt>$not_null</tt> is <tt>true</tt> column will be set to <tt>NOT NULL</tt>.
+<tt>$length</tt> and <tt>$scale</tt> control the maximum lengths of character or decimal types (see below).
+Other options available to refine the column definition:
+  langid - character set/collation to use
+  sorted - whether this column will be used to order by
+'''langid''' is mapped to real database values by the "dblanguages" configuration option. The database may not be able to order the request column type in which case, if <tt>sorted</tt> is true, the database may use a substitute column type.
+<tt>$data_type</tt> is the SQL type. The types are constants defined by this module, to import them use:
+  use EPrints::Database qw( :sql_types );
+Supported types (n = requires <tt>$length</tt> argument):
+Character data: <tt>SQL_VARCHAR(n)</tt>, <tt>SQL_LONGVARCHAR</tt>, <tt>SQL_CLOB</tt>.
+Binary data: <tt>SQL_VARBINARY(n)</tt>, <tt>SQL_LONGVARBINARY</tt>.
+Integer data: <tt>SQL_TINYINT</tt>, <tt>SQL_SMALLINT</tt>, <tt>SQL_INTEGER</tt>, <tt>SQL_BIGINT</tt>.
+Floating-point data: <tt>SQL_REAL</tt>, <tt>SQL_DOUBLE</tt>.
- $success = $db-&gt;drop_sequence( $seq_name )
+Time data: <tt>SQL_DATE</tt>, <tt>SQL_TIME</tt>.
-Deletes a sequence object.
+The actual column types used will be database-specific.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 360: / Line 473: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_column -->
+<!-- Pod2Wiki=head_basic_sql_operations -->
-===drop_column===
+===Basic SQL Operations===
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_do -->
+====do====
-  $success = $db-&gt;drop_column( $table, $column )
+  $success = $db-&gt;do( $sql )
-Drops a column from a table.
+Execute the given <tt>$sql</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 373: / Line 495: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_primary_key -->
+<!-- Pod2Wiki=item_prepare -->
-===get_primary_key===
+====prepare====
-  @columns = $db-&gt;get_primary_key( $tablename )
+  $sth = $db-&gt;prepare( $sql )
-Returns the list of column names that comprise the primary key for $tablename.
+Prepare the given <tt>$sql</tt> and return a handle on it.
-Returns empty list if no primary key exists.
+Use the <tt>execute</tt> method on the returned {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}} handle to execute the SQL:
+  my $sth = $db-&gt;prepare_select( "SELECT 'Hello, World'" );
+  $sth-&gt;execute;
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 388: / Line 513: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_index -->
+<!-- Pod2Wiki=item_prepare_select -->
-===create_index===
+====prepare_select====
+ $sth = $db-&gt;prepare_select( $sql, [ %options ] )
+Prepare a <tt>SELECT</tt> statement <tt>$sql</tt> and return a handle to it. After  preparing a statement use <tt>execute()</tt> to execute it.
+Returns a {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}} statement handle.
+The <tt>LIMIT</tt> SQL keyword is not universally supported, to specify this  use the <tt>limit</tt> option.
- $success = $db-&gt;create_index( $tablename, @columns )
+Options:
-Creates an index over @columns for $tablename. Returns true on success.
+  limit - limit the number of rows returned
+  offset - return '''limit''' number of rows after offset
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 401: / Line 535: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_unique_index -->
+<!-- Pod2Wiki=item_execute -->
-===create_unique_index===
+====execute====
-  $success = $db-&gt;create_unique_index( $tablename, @columns )
+  $success = $db-&gt;execute( $sth, $sql )
-Creates a unique index over @columns for $tablename. Returns true on success.
+Execute the SQL prepared earlier in the <tt>$sth</tt>. <tt>$sql</tt> is only  required for debugging purposes.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 414: / Line 548: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item__update -->
+<!-- Pod2Wiki=item_update -->
-===_update===
+====update====
-  $success = $db-&gt;_update( $tablename, $keycols, $keyvals, $columns, @values )
+  $success = $db-&gt;update( $dataset, $data, $changed )
-UPDATES $tablename where $keycols equals $keyvals.
+Updates a <tt>EPrints::DataObj</tt> from <tt>$dataset</tt> with the given <tt>$data</tt>.  The primary key field (e.g. <tt>eprintid</tt>) value must be included.
-This method is internal.
+Updates the <tt>ordervalues</tt> if the <tt>$dataset</tt> is  {{API:PodLink|file=EPrints/DataSet#ordered|package_name=EPrints::DataSet#ordered|section=|text=ordered}}.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 429: / Line 563: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item__update_quoted -->
+<!-- Pod2Wiki=item__update -->
-===_update_quoted===
+====_update====
-  $success = $db-&gt;_update_quoted( $tablename, $keycols, $keyvals, $columns, @qvalues )
+  $rows = $db-&gt;_update( $tablename, $keycols, $keyvals, $columns, @values )
-UPDATES $tablename where $keycols equals $keyvals. Won't quote $keyvals or @qvalues before use - use this method with care!
+Updates <tt>$columns</tt> in <tt>$tablename</tt> with <tt>@values</tt> where <tt>$keycols</tt>  equals <tt>$keyvals</tt> and returns the number of rows affected.
-This method is internal.
+N.B. If no rows are affected, the result is still <tt>true</tt>,  see {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}}'s <tt>execute()</tt> method.
+This is an internal method.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 445: / Line 581: @@
 </div>
 <!-- Pod2Wiki=item_insert -->
-===insert===
+====insert====
   $success = $db-&gt;insert( $table, $columns, @values )
-Inserts values into the table $table. If $columns is defined it will be used as a list of columns to insert into. @values is a list of arrays containing values to insert.
+Inserts <tt>@values</tt> into the table <tt>$table</tt>. If <tt>$columns</tt> is defined  it will be used as a list of columns to insert into. <tt>@values</tt> is a  list of arrays containing values to insert. These will be quoted before  insertion.
-Values will be quoted before insertion.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 460: / Line 594: @@
 </div>
 <!-- Pod2Wiki=item_insert_quoted -->
-===insert_quoted===
+====insert_quoted====
   $success = $db-&gt;insert_quoted( $table, $columns, @qvalues )
-Inserts values into the table $table. If $columns is defined it will be used as a list of columns to insert into. @qvalues is a list of arrays containing values to insert.
+Inserts values into the table <tt>$table</tt>. If <tt>$columns</tt> is defined it  will be used as a list of columns to insert into. <tt>@qvalues</tt> is a  list of arrays containing values to insert. These will NOT be quoted  before insertion - care must be exercised!
-Values will NOT be quoted before insertion - care must be exercised!
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 475: / Line 607: @@
 </div>
 <!-- Pod2Wiki=item_delete_from -->
-===delete_from===
+====delete_from====
   $success = $db-&gt;delete_from( $table, $columns, @values )
-Perform a SQL DELETE FROM $table using $columns to build a where clause. @values is a list of array references of values in the same order as $columns.
+Perform a SQL <tt>DELETE FROM</tt> <tt>$table</tt> using <tt>$columns</tt> to build a  where clause. <tt>@values</tt> is a list of array references of values in  the same order as <tt>$columns</tt>.
-If you want to clear a table completely use clear_table().
+If you want to clear a table completely use <tt>clear_table()</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 489: / Line 621: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_add_record -->
+<!-- Pod2Wiki=item_count_table -->
-===add_record===
+====count_table====
+ $n = $db-&gt;count_table( $tablename )
+Return the number of rows in the specified SQL table with  <tt>$tablename</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_clear_table -->
+====clear_table====
+ $db-&gt;clear_table( $tablename )
+Clears all records from the given table with <tt>$tablename</tt>. Use with  caution!
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $success = $db-&gt;add_record( $dataset, $data )
-Add the given data as a new record in the given dataset. $data is a reference to a hash containing values structured for a record in the that dataset.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_quoting -->
+===Quoting===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 503: / Line 657: @@
 </div>
 <!-- Pod2Wiki=item_prep_int -->
-===prep_int===
+====prep_int====
   $mungedvalue = EPrints::Database::prep_int( $value )
-Escape a numerical value for SQL. undef becomes NULL. Anything else becomes a number (zero if needed).
+Escape numerical <tt>$value</tt> for an SQL statement. <tt>undef</tt> becomes  <tt>NULL</tt>. Anything else becomes a number (zero if needed).
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 516: / Line 670: @@
 </div>
 <!-- Pod2Wiki=item_prep_value -->
-===prep_value===
+====prep_value====
   $mungedvalue = EPrints::Database::prep_value( $value )
-Escape a value for SQL. Modify value such that " becomes \" and \  becomes \\ and ' becomes \'
+Escape <tt>$value</tt> for an SQL statement. Modify value such that <tt>"</tt>  becomes <tt>\"</tt> and <tt>\</tt> becomes <tt>\\</tt> and <tt>'</tt> becomes <tt>\'</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 529: / Line 683: @@
 </div>
 <!-- Pod2Wiki=item_prep_like_value -->
-===prep_like_value===
+====prep_like_value====
   $mungedvalue = EPrints::Database::prep_like_value( $value )
-Escape an value for an SQL like field. In addition to ' " and \ also  escapes % and _
+Escape <tt>$value</tt> for an SQL <tt>LIKE</tt> clause. In addition to <tt>'</tt> <tt>"</tt>  and <tt>\</tt> also escapes <tt>%</tt> and <tt>_</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 542: / Line 696: @@
 </div>
 <!-- Pod2Wiki=item_quote_value -->
-===quote_value===
+====quote_value====
   $str = $db-&gt;quote_value( $value )
-Return a quoted value. To quote a 'like' value you should do:
+Return a quoted version of <tt>$value</tt>. To quote a <tt>LIKE</tt> value  you should use:
-  my $str = $database-&gt;quote_value( EPrints::Database::prep_like_value( $foo ) . '%' );
+  $db-&gt;quote_value( EPrints::Database::prep_like_value( $foo ) . '%' );
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 557: / Line 711: @@
 </div>
 <!-- Pod2Wiki=item_quote_int -->
-===quote_int===
+====quote_int====
   $str = $db-&gt;quote_int( $value )
-Return a quoted integer value
+Return a quoted integer for <tt>$value</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 570: / Line 724: @@
 </div>
 <!-- Pod2Wiki=item_quote_binary -->
-===quote_binary===
+====quote_binary====
   $str = $db-&gt;quote_binary( $bytes )
-Some databases (Oracle/PostgreSQL) require transforms of binary data to work correctly.
+Some databases (Oracle/PostgreSQL) require transforms of binary data  to work correctly.
-This method should be called on data containing nul bytes or back-slashes before being passed on {{API:PodLink|file=|package_name=|section=quote_value|text=/quote_value}}.
+This method should be called on data <tt>$bytes</tt> containing null bytes  or back-slashes before being passed on [[API:EPrints/Database#quote_value|quote_value]].
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 585: / Line 739: @@
 </div>
 <!-- Pod2Wiki=item_quote_ordervalue -->
-===quote_ordervalue===
+====quote_ordervalue====
   $str = $db-&gt;quote_ordervalue( $field, $value )
-Some databases (Oracle) can't order by CLOBS so need special treatment when creating the ordervalues tables. This method allows any fixing-up required for string data before it's inserted.
+Some databases (Oracle) can't order by <tt>CLOB</tt>s so need special  treatment when creating the ordervalues tables. This method allows any  fixing-up required for string data <tt>$value</tt> for <tt>$field</tt> before it's  inserted.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 598: / Line 752: @@
 </div>
 <!-- Pod2Wiki=item_quote_identifier -->
-===quote_identifier===
+====quote_identifier====
   $str = $db-&gt;quote_identifier( @parts )
-Quote a database identifier (e.g. table names). Multiple @parts will be joined by dot.
+Quote a database identifier (e.g. table names). Multiple <tt>@parts</tt>  will be joined by dots (<tt>.</tt>).
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 610: / Line 764: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_update -->
+<!-- Pod2Wiki=item_prepare_regexp -->
-===update===
+====prepare_regexp====
-  $success = $db-&gt;update( $dataset, $data, $changed, $insert )
+  $sql = $db-&gt;prepare_regexp( $col, $value )
-Updates a record in the database with the given $data. Obviously the value of the primary key must be set.
+The syntax used for regular expressions varies across databases. This  method takes two quoted string and returns a SQL expression that will  apply the quoted regexp <tt>$value</tt> to the quoted column <tt>$col</tt>.
-This also updates the text indexes and the ordering keys.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 625: / Line 777: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_remove -->
+<!-- Pod2Wiki=item_sql_as -->
-===remove===
+====sql_as====
-  $success = $db-&gt;remove( $dataset, $id )
+  $sql = $db-&gt;sql_AS()
-Attempts to remove the record with the primary key $id from the  specified dataset.
+Returns the syntactic glue to use when aliasing. SQL 92 databases will  happily use <tt>AS</tt> but some databases (Oracle) will not accept it.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 638: / Line 790: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_counters -->
+<!-- Pod2Wiki=item_sql_like -->
-===create_counters===
+====sql_like====
+ $sql = $db-&gt;sql_LIKE()
+Returns the syntactic glue to use when making a case-insensitive  <tt>LIKE</tt>. PostgreSQL requires <tt>ILIKE</tt> while everything else uses  <tt>LIKE</tt> and the column collation.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $success = $db-&gt;create_counters
-Create the counters used to store the highest current id of eprints, users etc.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_counters -->
+===Counters===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 651: / Line 812: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_counter -->
+<!-- Pod2Wiki=item_counter_current -->
-===has_counter===
+====counter_current====
-  $success = $db-&gt;has_counter( $counter )
+  $n = $db-&gt;counter_current( $counter )
-Returns true if $counter exists.
+Return the value of the previous counter_next on <tt>$counter</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 664: / Line 825: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_counter -->
+<!-- Pod2Wiki=item_counter_next -->
-===create_counter===
+====counter_next====
-  $success = $db-&gt;create_counter( $name )
+  $n = $db-&gt;counter_next( $counter )
-Create and initialise to zero a new counter called $name.
+Return the next unused value for the named <tt>$counter</tt>. Returns  <tt>undef</tt> if the <tt>$counter</tt> doesn't exist.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 677: / Line 838: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_remove_counters -->
+<!-- Pod2Wiki=item_counter_minimum -->
-===remove_counters===
+====counter_minimum====
-  $success = $db-&gt;remove_counters
+  $db-&gt;counter_minimum( $counter, $value )
-Destroy all counters.
+Ensure that the <tt>$counter</tt> is set no lower than <tt>$value</tt>. This is  used when importing eprints which may not be in scrict sequence.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 690: / Line 851: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_counter -->
+<!-- Pod2Wiki=item_counter_reset -->
-===drop_counter===
+====counter_reset====
-  $success = $db-&gt;drop_counter( $name )
+  $db-&gt;counter_reset( $counter )
-Destroy the counter named $name.
+Reset the <tt>$counter</tt>. Use with caution.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 704: / Line 865: @@
 </div>
 <!-- Pod2Wiki=item_next_doc_pos -->
-===next_doc_pos===
+====next_doc_pos====
   $n = $db-&gt;next_doc_pos( $eprintid )
-Return the next unused document pos for the given eprintid.
+Return the next unused document position for the given <tt>$eprintid</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 716: / Line 877: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_current -->
+<!-- Pod2Wiki=head_dataset_data -->
-===counter_current===
+===Dataset Data===
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_exists -->
+====exists====
-  $n = $db-&gt;counter_current( $counter )
+  $boolean = $db-&gt;exists( $dataset, $id )
-Return the value of the previous counter_next on $counter.
+Return <tt>true</tt> if there exists an [[API:EPrints/DataObj|EPrints::DataObj]] from the  <tt>$dataset</tt> with its primary key set to <tt>$id</tt>. Otherwise, return  <tt>false</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 729: / Line 899: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_next -->
+<!-- Pod2Wiki=item_add_record -->
-===counter_next===
+====add_record====
-  $n = $db-&gt;counter_next( $counter )
+  $success = $db-&gt;add_record( $dataset, $data )
-Return the next unused value for the named counter. Returns undef if  the counter doesn't exist.
+Add the given <tt>$data</tt> as a new record in the given <tt>$dataset</tt>.  <tt>$data</tt> is a reference to a hash containing values structured for a  record in the that <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 742: / Line 912: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_minimum -->
+<!-- Pod2Wiki=item_remove -->
-===counter_minimum===
+====remove====
-  $db-&gt;counter_minimum( $counter, $value )
+  $success = $db-&gt;remove( $dataset, $id )
-Ensure that the counter is set no lower than $value. This is used when importing eprints which may not be in scrict sequence.
+Attempts to remove the [[API:EPrints/DataObj|EPrints::DataObj]] with the primary key <tt>$id</tt>  from the specified <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 755: / Line 925: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_reset -->
+<!-- Pod2Wiki=head_searching_caching_and_object_retrieval -->
-===counter_reset===
+===Searching, caching and object retrieval===
- $db-&gt;counter_reset( $counter )
-Reset the counter. Use with caution.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 769: / Line 935: @@
 </div>
 <!-- Pod2Wiki=item_cache_exp -->
-===cache_exp===
+====cache_exp====
   $searchexp = $db-&gt;cache_exp( $cacheid )
-Return the serialised Search of a the cached search with id $cacheid. Return undef if the id is invalid or expired.
+Return the serialised search of a the cached search with <tt>$cacheid</tt>. Return <tt>undef</tt> if the <tt>$cacheid</tt> is invalid or expired.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 782: / Line 948: @@
 </div>
 <!-- Pod2Wiki=item_cache -->
-===cache===
+====cache====
   $cacheid = $db-&gt;cache( $searchexp, $dataset, $srctable, [$order], [$list] )
-Create a cache of the specified search expression from the SQL table $srctable.
+Create a cache of the specified search expression from the SQL table <tt>$srctable</tt>.
-If $order is set then the cache is ordered by the specified fields. For example "-year/title" orders by year (descending). Records with the same year are ordered by title.
+If <tt>$order</tt> is set then the cache is ordered by the specified fields.  For example <tt>-year/title</tt> orders by year (descending). Records with  the same year are ordered by title.
-If $srctable is set to "LIST" then order is ignored and the list of ids is taken from the array reference $list.
+If <tt>$srctable</tt> is set to <tt>LIST</tt> then order is ignored and the list  of IDs is taken from the array reference <tt>$list</tt>.
-If $srctable is set to "ALL" every matching record from $dataset is added to the cache, optionally ordered by $order.
+If <tt>$srctable</tt> is set to <tt>ALL</tt> every matching record from $dataset  is added to the cache, optionally ordered by <tt>$order</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 801: / Line 967: @@
 </div>
 <!-- Pod2Wiki=item_cache_table -->
-===cache_table===
+====cache_table====
   $tablename = $db-&gt;cache_table( $id )
-Return the SQL table used to store the cache with id $id.
+Return the name of the SQL table used to store the cache with <tt>$id</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 813: / Line 979: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_index_ids -->
+<!-- Pod2Wiki=item_cache_userid -->
-===get_index_ids===
+====cache_userid====
-  $ids = $db-&gt;get_index_ids( $table, $condition )
+  $userid = $db-&gt;cache_userid( $id )
-Return a reference to an array of the distinct primary keys from the given SQL table which match the specified condition.
+Returns the <tt>userid</tt> associated with the cache with <tt>$id</tt> if that  cache exists.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 826: / Line 992: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_search -->
+<!-- Pod2Wiki=item_get_cachemap -->
-===search===
+====get_cachemap====
- $ids = $db-&gt;search( $keyfield, $tables, $conditions, [$main_table_alias] )
-Return a reference to an array of ids - the results of the search specified by $conditions accross the tables specified in the $tables hash where keys are tables aliases and values are table names.
-If no table alias is passed then M is assumed.
+ $cachemap = $db-&gt;get_cachemap( $id )
+Return the cachemap with $&lt;id&gt;.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 841: / Line 1,005: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_cache -->
+<!-- Pod2Wiki=item_search -->
-===drop_cache===
+====search====
+ $ids = $db-&gt;search( $keyfield, $tables, $conditions, [ $main_table_alias ] )
+Return a reference to an array of <tt>$keyfield</tt> IDs - the results of  the search specified by <tt>$conditions</tt> across the tables specified in  the <tt>$tables</tt> hash where keys are tables aliases and values are table  names.
- $db-&gt;drop_cache( $id )
+If no <tt>$main_table_alias</tt> is specified then <tt>M</tt> is assumed.
-Remove the cached search with the given id.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 854: / Line 1,020: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_count_table -->
+<!-- Pod2Wiki=item_drop_cache -->
-===count_table===
+====drop_cache====
-  $n = $db-&gt;count_table( $tablename )
+  $db-&gt;drop_cache( $id )
-Return the number of rows in the specified SQL table.
+Remove the cached search with the given <tt>$id</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 868: / Line 1,034: @@
 </div>
 <!-- Pod2Wiki=item_from_cache -->
-===from_cache===
+====from_cache====
-  $foo = $db-&gt;from_cache( $dataset, $cacheid, [$offset], [$count], [$justids] )
+  $items = $db-&gt;from_cache( $dataset, $cacheid, [ $offset, $count, $justids ] )
-Return a reference to an array containing all the items from the given dataset that have id's in the specified cache. The cache may be  specified either by id or serialised search expression.
+Return a reference to an array containing all the items from the given  <tt>$dataset</tt> that have IDs in the cache specified by <tt>$cacheid</tt>. The  cache may be specified either by ID or serialised search expression.
-$offset is an offset from the start of the cache and $count is the number of records to return.
+<tt>$offset</tt> is an offset from the start of the cache and <tt>$count</tt> is  the number of records to return.
-If $justids is true then it returns just an ref to an array of the record ids, not the objects.
+If <tt>$justids</tt> is <tt>true</tt> then it returns just a reference to an array  of the record IDs and not the objects themselves.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 885: / Line 1,051: @@
 </div>
 <!-- Pod2Wiki=item_drop_orphan_cache_tables -->
-===drop_orphan_cache_tables===
+====drop_orphan_cache_tables====
   $c = $db-&gt;drop_orphan_cache_tables
-Drop tables called "cacheXXX" where XXX is an integer. Returns the number of tables dropped.
+Drop tables called <tt>cacheXXX</tt> where <tt>XXX</tt> is an integer. Returns the  number of cache tables dropped.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 898: / Line 1,064: @@
 </div>
 <!-- Pod2Wiki=item_get_single -->
-===get_single===
+====get_single====
   $obj = $db-&gt;get_single( $dataset, $id )
-Return a single item from the given dataset. The one with the specified id.
+Return a single &lt;EPrints::DataObj&gt; from the given <tt>$dataset</tt> with primary key set to <tt>$id</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 911: / Line 1,077: @@
 </div>
 <!-- Pod2Wiki=item_get_all -->
-===get_all===
+====get_all====
   $items = $db-&gt;get_all( $dataset )
-Returns a reference to an array with all the items from the given dataset.
+Returns a reference to an array with all the &lt;EPrints::DataObj&gt;s from  the given <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 924: / Line 1,090: @@
 </div>
 <!-- Pod2Wiki=item_get_cache_ids -->
-===get_cache_ids===
+====get_cache_ids====
   @ids = $db-&gt;get_cache_ids( $dataset, $cachemap, $offset, $count )
-Returns a list of $count ids from $cache_id starting at $offset and in the order in the cachemap.
+Returns a list of <tt>$count</tt> IDs from <tt>$cache_id</tt> starting at  <tt>$offset</tt> and in the order in the <tt>$cachemap</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 937: / Line 1,103: @@
 </div>
 <!-- Pod2Wiki=item_get_dataobjs -->
-===get_dataobjs===
+====get_dataobjs====
-  @dataobjs = $db-&gt;get_dataobjs( $dataset [, $id [, $id ] ] )
+  @dataobjs = $db-&gt;get_dataobjs( $dataset, [ $id, $id, ... ] )
-Retrieves the records in $dataset with the given $id(s). If an $id doesn't exist in the database it will be ignored.
+Retrieves the records in <tt>$dataset</tt> with the given <tt>$id</tt>(s). If an  <tt>$id</tt> doesn't exist in the database it will be ignored.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 950: / Line 1,116: @@
 </div>
 <!-- Pod2Wiki=item_get_values -->
-===get_values===
+====get_values====
-  $foo = $db-&gt;get_values( $field, $dataset )
+  $values = $db-&gt;get_values( $field, $dataset )
-Return a reference to an array of all the distinct values of the  EPrints::MetaField specified.
+Return a reference to an array of all the distinct values of the  [[API:EPrints/MetaField|EPrints::MetaField]] <tt>$field</tt> for the <tt>$dataset</tt> specified.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 963: / Line 1,129: @@
 </div>
 <!-- Pod2Wiki=item_sort_values -->
-===sort_values===
+====sort_values====
- $values = $db-&gt;sort_values( $field, $values [, $langid ] )
-ALPHA!!! Liable to API change!!!
-Sorts and returns the list of $values using the database.
+ $values = $db-&gt;sort_values( $field, $values, [ $langid ] )
+Sorts and returns the list of <tt>$values</tt> using the database.
-$field is used to get the order value for each value. $langid (or $session-&gt;get_langid if unset) is used to determine the database collation to use when sorting the resulting order values.
+<tt>$field</tt> is used to get the order value for each value. <tt>$langid</tt>  (or $session-&gt;get_langid if unset) is used to determine the database  collation to use when sorting the resulting order values.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 980: / Line 1,144: @@
 </div>
 <!-- Pod2Wiki=item_get_ids_by_field_values -->
-===get_ids_by_field_values===
+====get_ids_by_field_values====
-  $ids = $db-&gt;get_ids_by_field_values( $field, $dataset [ %opts ] )
+  $ids = $db-&gt;get_ids_by_field_values( $field, $dataset, [ %opts ] )
-Return a reference to a hash table where the keys are field value ids and the value is a reference to an array of ids.
+Return a reference to a hash table where the keys are specified  <tt>$datasets</tt>'s <tt>$field</tt> value IDs and the values are references to  arrays of IDs.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 992: / Line 1,156: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_do -->
+<!-- Pod2Wiki=item_dequeue_events -->
-===do===
+====dequeue_events====
-  $success = $db-&gt;do( $sql )
+  @events = $db-&gt;dequeue_events( $n )
-Execute the given SQL.
+Attempt to dequeue upto <tt>$n</tt> events. May return between <tt>0</tt> and  <tt>$n</tt> events depending on parallel processes and how many events are  remaining in the queue.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,005: / Line 1,169: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prepare -->
+<!-- Pod2Wiki=item_ci_lookup -->
-===prepare===
+====ci_lookup====
+ $value = $db-&gt;ci_lookup( $field, $value )
+This is a hacky method to support case-insensitive lookup for usernames, emails, etc.  It returns the actual case-sensitive version of <tt>$value</tt> if there is a case-insensitive match for the <tt>$field</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $sth = $db-&gt;prepare( $sql )
-Prepare the given $sql and return a handle on it.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_password_validation_and_secret_fields -->
+===Password Validation and Secret Fields===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 1,018: / Line 1,191: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prepare_select -->
+<!-- Pod2Wiki=item_valid_login -->
-===prepare_select===
+====valid_login====
+ $db-&gt;valid_login( $username, $password )
+Returns whether the clear-text <tt>$password</tt> matches the stored crypted  password for the <tt>$username</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $sth = $db-&gt;prepare_select( $sql [, %options ] )
-Prepare a SELECT statement $sql and return a handle to it. After preparing a statement use execute() to execute it.
-The LIMIT SQL keyword is not universally supported, to specify a LIMIT you must use the '''limit''' option.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_secret_matches -->
+====secret_matches====
-Options:
+ $db-&gt;secret_matches( $dataobj, $fieldname, $token [, $callback ] )
+Returns whether the clear-text <tt>$token</tt> matches the stored crypted  field with <tt>$fieldname</tt> for the <tt>$dataobj</tt> according to the  <tt>$callback</tt> function.
+If not set, <tt>$callback</tt> defaults to [[API:EPrints/Utils#crypt_equals|EPrints::Utils#crypt_equals]].
-  limit - limit the number of rows returned
-  offset - return '''limit''' number of rows after offset
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 1,038: / Line 1,219: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_execute -->
+<!-- Pod2Wiki=item_is_secret_set -->
-===execute===
+====is_secret_set====
-  $success = $db-&gt;execute( $sth, $sql )
+  $boolean = $db-&gt;is_secret_set( $dataobj, $fieldname )
-Execute the SQL prepared earlier. $sql is only passed in for debugging purposes.
+Returns a boolean for whether the secret <tt>$fieldname</tt> for <tt>$dataobj</tt>  has a value set.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,051: / Line 1,232: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_dataset -->
+<!-- Pod2Wiki=head_database_schema_manipulation -->
-===has_dataset===
+===Database Schema Manipulation===
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_has_sequence -->
+====has_sequence====
+ $boolean = $db-&gt;has_sequence( $name )
+Returns <tt>true</tt> if a sequence of the given <tt>$name</tt> exists in the  database. Otherwise, returns <tt>false</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $db-&gt;has_dataset( $dataset )
+<!-- Pod2Wiki= -->
-Returns true if $dataset exists in the database or has no database tables.
+</div>
+<!-- Pod2Wiki=item_create_sequence -->
+====create_sequence====
-This does not check that all fields are configured - see has_field().
+ $success = $db-&gt;create_sequence( $name )
+Creates a new sequence object with <tt>$name</tt> and initialises to zero.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,066: / Line 1,267: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_field -->
+<!-- Pod2Wiki=item_drop_sequence -->
-===has_field===
+====drop_sequence====
-  $db-&gt;has_field( $dataset, $field )
+  $success = $db-&gt;drop_sequence( $name )
-Returns true if $field is in the database for $dataset.
+Deletes a sequence object with <tt>$name</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,079: / Line 1,280: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_add_field -->
+<!-- Pod2Wiki=item_has_column -->
-===add_field===
+====has_column====
+ $boolean = $db-&gt;has_column( $table, $column )
+Return <tt>true</tt> if the named <tt>$table</tt> has the named <tt>$column</tt> in the  database.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $db-&gt;add_field( $dataset, $field [, $force ] )
+<!-- Pod2Wiki= -->
-Add $field to $dataset's tables.
+</div>
+<!-- Pod2Wiki=item_drop_column -->
+====drop_column====
-If $force is true will modify/replace an existing column (use with care!).
+ $success = $db-&gt;drop_column( $table, $column )
+Drops the named <tt>$column</tt> from the named <tt>$table</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,094: / Line 1,306: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_remove_field -->
+<!-- Pod2Wiki=item_get_primary_key -->
-===remove_field===
+====get_primary_key====
+ @columns = $db-&gt;get_primary_key( $tablename )
+Returns a list of column names that comprise the primary key for  the <tt>$tablename</tt>.
- $db-&gt;remove_field( $dataset, $field )
+Returns an empty list if no primary key exists.
-Remove $field from $dataset's tables.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,107: / Line 1,321: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_rename_field -->
+<!-- Pod2Wiki=item_index_name -->
-===rename_field===
+====index_name====
-  $ok = $db-&gt;rename_field( $dataset, $field, $old_name )
+  $name = $db-&gt;index_name( $table, @cols )
-Rename a $field in the database from it's old name $old_name.
+Returns the name of the first index that starts with named columns  <tt>@cols</tt> in the named <tt>$table</tt>.
-Returns true if the field was successfully renamed.
+Returns <tt>undef</tt> if no index exists.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,122: / Line 1,336: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_exists -->
+<!-- Pod2Wiki=item_get_index_ids -->
-===exists===
+====get_index_ids====
-  $boolean = $db-&gt;exists( $dataset, $id )
+  $ids = $db-&gt;get_index_ids( $table, $condition )
-Return true if a record with the given primary key exists in the dataset, otherwise false.
+Return a reference to an array of the distinct primary keys from the named SQL <tt>$table</tt> which match the specified <tt>$condition</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,135: / Line 1,349: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_set_debug -->
+<!-- Pod2Wiki=item_create_index -->
-===set_debug===
+====create_index====
-  $db-&gt;set_debug( $boolean )
+  $success = $db-&gt;create_index( $table, @columns )
-Set the SQL debug mode to true or false.
+Creates an index over <tt>@columns</tt> for named <tt>$table</tt>. Returns <tt>true</tt>  on success, <tt>false</tt> otherwise.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,148: / Line 1,362: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_version_table -->
+<!-- Pod2Wiki=item_create_unique_index -->
-===create_version_table===
+====create_unique_index====
-  $db-&gt;create_version_table
+  $success = $db-&gt;create_unique_index( $tablename, @columns )
-Make the version table (and set the only value to be the current version of eprints).
+Creates a unique index over <tt>@columns</tt> for named <tt>$table</tt>. Returns  <tt>true</tt> on success, <tt>false</tt> otherwise.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,161: / Line 1,375: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_version_table -->
+<!-- Pod2Wiki=item_create_foreign_key -->
-===drop_version_table===
+====create_foreign_key====
+ $ok = $db-&gt;create_foreign_key( $main_table, $table, $key_field )
+Create a foreign key relationship between named <tt>$main_table</tt> and  named <tt>$table</tt> using <tt>$key_field</tt>.
-  $db-&gt;drop_version_table
+This will cause records in <tt>$table</tt> to be deleted if the equivalent  record is deleted from <tt>$main_table</tt>.
-Drop the version table.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,174: / Line 1,390: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_set_version -->
+<!-- Pod2Wiki=item_get_tables -->
-===set_version===
+====get_tables====
+ @tables = $db-&gt;get_tables( [ $dbname ] )
+Returns a list of all the tables in the database.
- $db-&gt;set_version( $versionid );
+<tt>$dbname</tt> specifies a particular database name of current connection has access to more than one database.
-Set the version id table in the SQL database to the given value (used by the upgrade script).
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,188: / Line 1,406: @@
 </div>
 <!-- Pod2Wiki=item_has_table -->
-===has_table===
+====has_table====
   $boolean = $db-&gt;has_table( $tablename )
-Return true if a table of the given name exists in the database.
+Returns boolean dependent on whether a table of the <tt>$tablename</tt>  exists in the database.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_create_table -->
+====create_table====
+ $success = $db-&gt;create_table( $tablename, $setkey, @fields );
+Creates a new table with <tt>$tablename</tt> based on <tt>@fields</tt>.
+The first <tt>$setkey</tt> number of fields are used for its primary key.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,200: / Line 1,433: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_column -->
+<!-- Pod2Wiki=item_drop_table -->
-===has_column===
+====drop_table====
+ $db-&gt;drop_table( @tables )
+Delete the named <tt>@tables</tt>. Use with caution!
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_rename_table -->
+====rename_table====
+ $db-&gt;rename_table( $table_from, $table_to )
+Renames the table named <tt>$table_from</tt> to <tt>$table_to</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_swap_table -->
+====swap_table====
+ $db-&gt;swap_table( $table_a, $table_b )
+Renames table named <tt>$table_a</tt> to <tt>$table_b</tt> and vice-versa.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_eprints_schema_manipulation -->
+===EPrints Schema Manipulation===
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_create_archive_tables -->
+====create_archive_tables====
+ $success = $db-&gt;create_archive_tables()
+Create all the SQL tables for all datasets.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_drop_archive_tables -->
+====drop_archive_tables====
+ $db-&gt;drop_archive_tables()
+Destroy all tables used by EPrints in the database.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_create_version_table -->
+====create_version_table====
+ $db-&gt;create_version_table
+Make the version table (and set the only value to be the current version of EPrints).
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_drop_version_table -->
+====drop_version_table====
-  $boolean = $db-&gt;has_column( $tablename, $columnname )
+  $db-&gt;drop_version_table
-Return true if the a table of the given name has a column named $columnname in the database.
+Drop the version table.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,213: / Line 1,533: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_index_name -->
+<!-- Pod2Wiki=item_has_dataset -->
-===index_name===
+====has_dataset====
-  $name = $db-&gt;index_name( $table, @columns )
+  $db-&gt;has_dataset( $dataset )
-Returns the name of the first index that starts with @columns on the $table table.
+Returns <tt>true</tt> if <tt>$dataset</tt> exists in the database and has all  expected tables including ordervalues and index tables.
-Returns undef if no index exists.
+This does not check that all fields are configured - see &lt;/has_field&gt;.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,228: / Line 1,548: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_table -->
+<!-- Pod2Wiki=item_has_dataset_index_tables -->
-===drop_table===
+====has_dataset_index_tables====
-  $db-&gt;drop_table( $tablename )
+  $db-&gt;has_dataset_index_tables( $dataset )
-Delete the named table. Use with caution!
+Returns <tt>true</tt> if index tables for <tt>$dataset</tt> exists of if this is  not indexable.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,241: / Line 1,561: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_clear_table -->
+<!-- Pod2Wiki=item_create_dataset_tables -->
-===clear_table===
+====create_dataset_tables====
-  $db-&gt;clear_table( $tablename )
+  $success = $db-&gt;create_dataset_tables( $dataset )
-Clears all records from the given table, use with caution!
+Creates all the SQL tables for the specified <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,254: / Line 1,574: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_rename_table -->
+<!-- Pod2Wiki=item_drop_dataset_tables -->
-===rename_table===
+====drop_dataset_tables====
-  $db-&gt;rename_table( $tablename, $newtablename )
+  $db-&gt;drop_dataset_tables( $dataset )
-Renames the table from the old name to the new one.
+Drops all the SQL tables for the specified <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,267: / Line 1,587: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_swap_table -->
+<!-- Pod2Wiki=item_create_dataset_index_tables -->
-===swap_table===
+====create_dataset_index_tables====
-  $db-&gt;swap_table( $table_a, $table_b )
+  $success = $db-&gt;create_dataset_index_tables( $dataset )
-Swap table a and table b.
+Creates all the index tables for the specified <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,280: / Line 1,600: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_tables -->
+<!-- Pod2Wiki=item_create_dataset_ordervalues_tables -->
-===get_tables===
+====create_dataset_ordervalues_tables====
-  @tables = $db-&gt;get_tables
+  $success = $db-&gt;create_dataset_ordervalues_tables( $dataset )
-Return a list of all the tables in the database.
+Creates all the ordervalues tables for the specified <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,293: / Line 1,613: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_version -->
+<!-- Pod2Wiki=item_has_field -->
-===get_version===
+====has_field====
-  $version = $db-&gt;get_version
+  $db-&gt;has_field( $dataset, $field )
-Return the version of eprints which the database is compatable with or undef if unknown (before v2.1).
+Returns <tt>true</tt> if <tt>$field</tt> is in the database for <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,306: / Line 1,626: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_is_latest_version -->
+<!-- Pod2Wiki=item_add_field -->
-===is_latest_version===
+====add_field====
+ $db-&gt;add_field( $dataset, $field, [ $force ] )
+Add <tt>$field</tt> to <tt>$dataset</tt>'s tables.
- $boolean = $db-&gt;is_latest_version
+If <tt>$force</tt> is <tt>true</tt> modify/replace an existing column. Use with  care!
-Return true if the SQL tables are in the correct configuration for this edition of eprints. Otherwise false.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,319: / Line 1,641: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_valid_login -->
+<!-- Pod2Wiki=item_remove_field -->
-===valid_login===
+====remove_field====
-  $db-&gt;valid_login( $username, $password )
+  $db-&gt;remove_field( $dataset, $field )
-Returns whether the clear-text $password matches the stored crypted password for $username.
+Remove <tt>$field</tt> from <tt>$dataset</tt>'s tables.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,332: / Line 1,654: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_server_version -->
+<!-- Pod2Wiki=item_rename_field -->
-===get_server_version===
+====rename_field====
+ $ok = $db-&gt;rename_field( $dataset, $field, $old_name )
+Rename the <tt>$field</tt> in the <tt>$dataset</tt> from its <tt>$old_name</tt>.
- $version = $db-&gt;get_server_version
+Returns <tt>true</tt> if the <tt>$field</tt> is successfully renamed.
-Return the database server version.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,345: / Line 1,669: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_default_charset -->
+<!-- Pod2Wiki=item_create_counters -->
-===get_default_charset===
+====create_counters====
-  $charset = $db-&gt;get_default_charset( LANGUAGE )
+  $success = $db-&gt;create_counters
-Return the character set to use for LANGUAGE.
+Create the counters used to store the highest current ID of eprints, users, etc.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Returns undef if character sets are unsupported.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_has_counter -->
+====has_counter====
+ $success = $db-&gt;has_counter( $counter )
+Returns <tt>true</tt> if <tt>$counter</tt> exists.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,360: / Line 1,695: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_default_collation -->
+<!-- Pod2Wiki=item_create_counter -->
-===get_default_collation===
+====create_counter====
+ $success = $db-&gt;create_counter( $name )
+Create and initialise to zero a new counter with <tt>$name</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $collation = $db-&gt;get_default_collation( LANGUAGE )
-Return the collation to use for LANGUAGE.
-Returns undef if collation is unsupported.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_remove_counters -->
+====remove_counters====
+ $success = $db-&gt;remove_counters
+Destroy all counters.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,375: / Line 1,721: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_driver_name -->
+<!-- Pod2Wiki=item_drop_counter -->
-===get_driver_name===
+====drop_counter====
+ $success = $db-&gt;drop_counter( $name )
+Destroy the counter named <tt>$name</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $driver = $db-&gt;get_driver_name
-Return the database driver name.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_user_messages -->
+===User Messages===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 1,388: / Line 1,743: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_dequeue_events -->
+<!-- Pod2Wiki=item_save_user_message -->
-===dequeue_events===
+====save_user_message====
-  @events = $db-&gt;dequeue_events( $n )
+  $message = $db-&gt;save_user_message( $userid, $m_type, $dom_m_data )
-Attempt to dequeue upto $n events. May return between 0 and $n events depending on parallel processes and how many events are remaining on the queue.
+Save user message provided in XML DOM object <tt>$dom_m_data</tt> as a  sanitized string in a [[API:EPrints/DataObj/Message|EPrints::DataObj::Message]] using <tt>$m_type</tt> to  define the message type and <tt>$userid</tt> for the ID of the user whose message it is.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,401: / Line 1,756: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prepare_regexp -->
+<!-- Pod2Wiki=item_get_user_messages -->
-===prepare_regexp===
+====get_user_messages====
-  $sql = $db-&gt;prepare_regexp( $quoted_column, $quoted_value )
+  @messages = $db-&gt;get_user_messages( $userid, %opts )
-The syntax used for regular expressions varies across databases. This method takes two '''quoted''' values and returns a SQL expression that will apply the regexp ($quoted_value) to the column ($quoted_column).
+Get the messages for a user with ID <tt>$userid</tt> and clear messages if <tt>$opt{clear}</tt> is set.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,414: / Line 1,769: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_sql_as -->
+<!-- Pod2Wiki=item_clear_user_messages -->
-===sql_as===
+====clear_user_messages====
-  $sql = $db-&gt;sql_AS()
+  $db-&gt;clear_user_messages( $userid )
-Returns the syntactic glue to use when aliasing. SQL 92 DBs will happilly use " AS " but some DBs (Oracle!) won't accept it.
+Clear all messages for user with ID <tt>$userid</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,427: / Line 1,782: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_sql_like -->
+<!-- Pod2Wiki=head_see_also -->
-===sql_like===
+==SEE ALSO==
+To access database-stored objects use the methods provided by the  following modules: [[API:EPrints/Repository|EPrints::Repository]], [[API:EPrints/DataSet|EPrints::DataSet]].
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
- $sql = $db-&gt;sql_LIKE()
-Returns the syntactic glue to use when making a case-insensitive LIKE. PostgreSQL requires "ILIKE" while everything else uses "LIKE" and the column collation.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_copyright -->
+==COPYRIGHT==
+{{API:Copyright}}
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>

Difference between revisions of "API:EPrints/Database"

Latest revision as of 21:20, 4 March 2022

Contents

NAME

DESCRIPTION

Cross-database Support

Quoting SQL Values

CONSTANTS

SQL_NULL

SQL_NOT_NULL

INSTANCE VARIABLES

$self->{session}

$self->{debug}

$self->{dbh}

METHODS

Database

new

create

build_connection_string

connect

disconnect

set_debug

set_version

get_version

is_latest_version

get_server_version

get_default_charset

get_default_collation

get_driver_name

error

retry_error

duplicate_error

begin

commit

rollback

type_info

get_column_type

Basic SQL Operations

do

prepare

prepare_select

execute

update

_update

insert

insert_quoted

delete_from

count_table

clear_table

Quoting

prep_int

prep_value

prep_like_value

quote_value

quote_int

quote_binary

quote_ordervalue

quote_identifier

prepare_regexp

sql_as

sql_like

Counters

counter_current

counter_next

counter_minimum

counter_reset

next_doc_pos

Dataset Data

exists

add_record

remove

Searching, caching and object retrieval

cache_exp

cache

cache_table

cache_userid

get_cachemap

search

drop_cache

from_cache