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]]<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 $Q_value");
+Where possible you should avoid quoting values yourself, instead use a  method that accepts unquoted values which will (safely) do the work  for you.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_constants -->
+==CONSTANTS==
+All the <tt>SQL_</tt> column types defined by Perl module {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}} and the  following:
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_sql_null -->
+===SQL_NULL===
+A column value is undefined.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_sql_not_null -->
+===SQL_NOT_NULL===
+A column value is defined.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Variables that are database quoted are prefixed with 'Q_'.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_instance_variables -->
+==INSTANCE VARIABLES==
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 45: / Line 101: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_build_connection_string -->
+<!-- Pod2Wiki=item_$self->{session} -->
-====$dbstr = EPrints::Database::build_connection_string( %params )====
+===$self-&gt;{session}===
+The [[API:EPrints/Session|EPrints::Session]] which is associated with this database  connection.
+<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_$self->{debug} -->
+===$self-&gt;{debug}===
+If <tt>true</tt> then SQL is logged.
+<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_$self->{dbh} -->
+===$self-&gt;{dbh}===
-Build the string to use to connect to the database via DBI. %params  must contain dbname, and may also contain dbport, dbhost and dbsock.
+The handle on the actual database connection.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 57: / Line 137: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create -->
+<!-- Pod2Wiki=head_methods -->
-====$db = $db-&gt;create( $username, $password )====
+==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 -->
-Create and connect to a new database using super user account $username and $password.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_database -->
+===Database===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 70: / Line 156: @@
 </div>
 <!-- Pod2Wiki=item_new -->
-====$db = EPrints::Database-&gt;new( $session )====
+====new====
+ $db = EPrints::Database-&gt;new( $repo, [ %opts ] )
 Create a connection to the database.
+Options:
+  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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_create -->
+====create====
+ $db = $db-&gt;create( $username, $password )
+Create and connect to a new database using user account <tt>$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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_build_connection_string -->
+====build_connection_string====
+ $dbstr = EPrints::Database::build_connection_string( %params )
+Build the string to use to connect to the database via {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}}.
+Parameters:
+ dbname - Database name (REQUIRED).
+ dbdriver - Database driver (e.g. mysql, Oracle, pgsql, default: mysql).
+ dbhost - Database host.  Assumes localhost if unset.
+ dbport - Port to connect to database host.  Assumes default for driver if unset.
+ dbsock - Socket file to connect to database through.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 82: / Line 205: @@
 </div>
 <!-- Pod2Wiki=item_connect -->
-====$foo = $db-&gt;connect====
+====connect====
+ $db-&gt;connect()
 Connects to the database.
@@ Line 94: / Line 218: @@
 </div>
 <!-- Pod2Wiki=item_disconnect -->
-====$foo = $db-&gt;disconnect====
+====disconnect====
-Disconnects from the EPrints database. Should always be done before any script exits.
+ $db-&gt;disconnect()
+Disconnects from the EPrints database. Should always be done before  any script exits.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 105: / Line 230: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_error -->
+<!-- Pod2Wiki=item_set_debug -->
-====$errstr = $db-&gt;error====
+====set_debug====
+ $db-&gt;set_debug( $boolean )
+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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_set_version -->
+====set_version====
+ $db-&gt;set_version( $versionid );
+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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_get_version -->
+====get_version====
+ $version = $db-&gt;get_version
+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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_is_latest_version -->
+====is_latest_version====
+ $boolean = $db-&gt;is_latest_version
+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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_get_server_version -->
+====get_server_version====
-Return a string describing the last SQL error.
+ $version = $db-&gt;get_server_version
+Return the database server version.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 117: / Line 295: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_begin -->
+<!-- Pod2Wiki=item_get_default_charset -->
-====$db-&gt;begin====
+====get_default_charset====
+ $charset = $db-&gt;get_default_charset
+Return the character set to use.
-Begin a transaction.
+Returns <tt>undef</tt> if character sets are unsupported.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 129: / Line 310: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_commit -->
+<!-- Pod2Wiki=item_get_default_collation -->
-====$db-&gt;commit====
+====get_default_collation====
+ $collation = $db-&gt;get_default_collation( $lang )
+Return the collation to use for language <tt>$lang</tt>.
-Commit the previous begun transaction.
+Returns <tt>undef</tt> if collation is unsupported.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 141: / Line 325: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_rollback -->
+<!-- Pod2Wiki=item_get_driver_name -->
-====$db-&gt;rollback====
+====get_driver_name====
-Rollback the partially completed transaction.
+ $driver = $db-&gt;get_driver_name
+Return the database driver name.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 153: / Line 338: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_archive_tables -->
+<!-- Pod2Wiki=item_error -->
-====$success = $db-&gt;create_archive_tables====
+====error====
-Create all the SQL tables for each dataset.
+ $errstr = $db-&gt;error()
+Return a string describing the last SQL error.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 165: / Line 351: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_archive_tables -->
+<!-- Pod2Wiki=item_retry_error -->
-====$db-&gt;drop_archive_tables()====
+====retry_error====
-Destroy all tables used by eprints in the database.
+ $boolean = $db-&gt;retry_error()
+Returns a boolean for whether the database error is a retry error.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 177: / Line 364: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_dataset_tables -->
+<!-- Pod2Wiki=item_duplicate_error -->
-====$success = $db-&gt;create_dataset_tables( $dataset )====
+====duplicate_error====
-Create all the SQL tables for a single dataset.
+ $boolean = $db-&gt;duplicate_error()
+Returns a boolean for whether the database error is a duplicate error.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 189: / Line 377: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_dataset_tables -->
+<!-- Pod2Wiki=item_begin -->
-====$db-&gt;drop_dataset_tables( $dataset )====
+====begin====
-Drop all the SQL tables for a single dataset.
+ $db-&gt;begin()
+Begin a transaction.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 201: / Line 390: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_dataset_index_tables -->
+<!-- Pod2Wiki=item_commit -->
-====$success = $db-&gt;create_dataset_index_tables( $dataset )====
+====commit====
-Create all the index tables for a single dataset.
+ $db-&gt;commit()
+Commit the previously begun transaction.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 213: / Line 403: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_dataset_ordervalues_tables -->
+<!-- Pod2Wiki=item_rollback -->
-====$success = $db-&gt;create_dataset_ordervalues_tables( $dataset )====
+====rollback====
-Create all the ordervalues tables for a single dataset.
+ $db-&gt;rollback()
+Rollback the partially completed transaction.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 226: / Line 417: @@
 </div>
 <!-- Pod2Wiki=item_type_info -->
-====$type_info = $db-&gt;type_info( DATA_TYPE )====
+====type_info====
+ $type_info = $db-&gt;type_info( $data_type )
 See {{API:PodLink|file=DBI|package_name=DBI|section=type_info|text=DBI/type_info}}.
@@ Line 238: / Line 430: @@
 </div>
 <!-- Pod2Wiki=item_get_column_type -->
-====$real_type = $db-&gt;get_column_type( NAME, TYPE, NOT_NULL, [ LENGTH/PRECISION ], [ SCALE ], %opts )====
+====get_column_type====
-Returns a SQL column definition for NAME of type TYPE, usually something like:
+ $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,$scale) [ NOT NULL ]
-If NOT_NULL is true column will be set "not null".
+If <tt>$not_null</tt> is <tt>true</tt> column will be set to <tt>NOT NULL</tt>.
-LENGTH/PRECISION and SCALE control the maximum lengths of character or decimal types (see below).
+<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:
@@ Line 253: / Line 446: @@
    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.
+'''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.
-TYPE is the SQL type. The types are constants defined by this module, to import them use:
+<tt>$data_type</tt> is the SQL type. The types are constants defined by this module, to import them use:
    use EPrints::Database qw( :sql_types );
-Supported types (n = requires LENGTH argument):
+Supported types (n = requires <tt>$length</tt> argument):
-Character data: SQL_VARCHAR(n), SQL_LONGVARCHAR.
+Character data: <tt>SQL_VARCHAR(n)</tt>, <tt>SQL_LONGVARCHAR</tt>, <tt>SQL_CLOB</tt>.
-Binary data: SQL_VARBINARY(n), SQL_LONGVARBINARY.
+Binary data: <tt>SQL_VARBINARY(n)</tt>, <tt>SQL_LONGVARBINARY</tt>.
-Integer data: SQL_TINYINT, SQL_SMALLINT, SQL_INTEGER, SQL_BIGINT.
+Integer data: <tt>SQL_TINYINT</tt>, <tt>SQL_SMALLINT</tt>, <tt>SQL_INTEGER</tt>, <tt>SQL_BIGINT</tt>.
-Floating-point data: SQL_REAL, SQL_DOUBLE.
+Floating-point data: <tt>SQL_REAL</tt>, <tt>SQL_DOUBLE</tt>.
-Time data: SQL_DATE, SQL_TIME.
+Time data: <tt>SQL_DATE</tt>, <tt>SQL_TIME</tt>.
 The actual column types used will be database-specific.
@@ Line 280: / Line 473: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_table -->
+<!-- Pod2Wiki=head_basic_sql_operations -->
-====$success = $db-&gt;create_table( $tablename, $dataset, $setkey, @fields );====
+===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 -->
-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_do -->
+====do====
+ $success = $db-&gt;do( $sql )
+Execute the given <tt>$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 294: / Line 495: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_sequence -->
+<!-- Pod2Wiki=item_prepare -->
-====$boolean = $db-&gt;has_sequence( $name )====
+====prepare====
+ $sth = $db-&gt;prepare( $sql )
+Prepare the given <tt>$sql</tt> and return a handle on it.
-Return true if a sequence of the given name exists in the database.
+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'" );
+  $sth-&gt;execute;
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 306: / Line 513: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_sequence -->
+<!-- Pod2Wiki=item_prepare_select -->
-====$success = $db-&gt;create_sequence( $seq_name )====
+====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.
-Creates a new sequence object initialised to zero.
+Options:
+  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 318: / Line 535: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_sequence -->
+<!-- Pod2Wiki=item_execute -->
-====$success = $db-&gt;drop_sequence( $seq_name )====
+====execute====
-Deletes a sequence object.
+ $success = $db-&gt;execute( $sth, $sql )
+Execute the SQL prepared earlier in the <tt>$sth</tt>. <tt>$sql</tt> is only  required for debugging purposes.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 330: / Line 548: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_column -->
+<!-- Pod2Wiki=item_update -->
-====$success = $db-&gt;drop_column( $table, $column )====
+====update====
+ $success = $db-&gt;update( $dataset, $data, $changed )
+Updates a <tt>EPrints::DataObj</tt> from <tt>$dataset</tt> with the given <tt>$data</tt>.  The primary key field (e.g. <tt>eprintid</tt>) value must be included.
-Drops a column from a table.
+Updates the <tt>ordervalues</tt> if the <tt>$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 342: / Line 563: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_primary_key -->
+<!-- Pod2Wiki=item__update -->
-====@columns = $db-&gt;get_primary_key( $tablename )====
+====_update====
+ $rows = $db-&gt;_update( $tablename, $keycols, $keyvals, $columns, @values )
+Updates <tt>$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.
-Returns the list of column names that comprise the primary key for $tablename.
+N.B. If no rows are affected, the result is still <tt>true</tt>,  see {{API:PodLink|file=DBI|package_name=DBI|section=|text=DBI}}'s <tt>execute()</tt> method.
-Returns empty list if no primary key exists.
+This is an internal method.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 356: / Line 580: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_index -->
+<!-- Pod2Wiki=item_insert -->
-====$success = $db-&gt;create_index( $tablename, @columns )====
+====insert====
-Creates an index over @columns for $tablename. Returns true on success.
+ $success = $db-&gt;insert( $table, $columns, @values )
+Inserts <tt>@values</tt> into the table <tt>$table</tt>. If <tt>$columns</tt> is defined  it will be used as a list of columns to insert into. <tt>@values</tt> is a  list of arrays containing values to insert. These will be quoted before  insertion.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 368: / Line 593: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_unique_index -->
+<!-- Pod2Wiki=item_insert_quoted -->
-====$success = $db-&gt;create_unique_index( $tablename, @columns )====
+====insert_quoted====
-Creates a unique index over @columns for $tablename. Returns true on success.
+ $success = $db-&gt;insert_quoted( $table, $columns, @qvalues )
+Inserts values into the table <tt>$table</tt>. If <tt>$columns</tt> is defined it  will be used as a list of columns to insert into. <tt>@qvalues</tt> is a  list of arrays containing values to insert. These will NOT be quoted  before insertion - care must be exercised!
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 380: / Line 606: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item__update -->
+<!-- Pod2Wiki=item_delete_from -->
-====$success = $db-&gt;_update( $tablename, $keycols, $keyvals, $columns, @values )====
+====delete_from====
+ $success = $db-&gt;delete_from( $table, $columns, @values )
+Perform a SQL <tt>DELETE FROM</tt> <tt>$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 <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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-UPDATES $tablename where $keycols equals $keyvals.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_count_table -->
+====count_table====
-This method is internal.
+ $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%; '>
@@ Line 394: / Line 634: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item__update_quoted -->
+<!-- Pod2Wiki=item_clear_table -->
-====$success = $db-&gt;_update_quoted( $tablename, $keycols, $keyvals, $columns, @qvalues )====
+====clear_table====
-UPDATES $tablename where $keycols equals $keyvals. Won't quote $keyvals or @qvalues before use - use this method with care!
+ $db-&gt;clear_table( $tablename )
+Clears all records from the given table with <tt>$tablename</tt>. Use with  caution!
-This method is internal.
+<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 -->
+===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 408: / Line 656: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_insert -->
+<!-- Pod2Wiki=item_prep_int -->
-====$success = $db-&gt;insert( $table, $columns, @values )====
+====prep_int====
+ $mungedvalue = EPrints::Database::prep_int( $value )
+Escape numerical <tt>$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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_prep_value -->
+====prep_value====
+ $mungedvalue = EPrints::Database::prep_value( $value )
+Escape <tt>$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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-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.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_prep_like_value -->
+====prep_like_value====
-Values will be quoted before insertion.
+ $mungedvalue = EPrints::Database::prep_like_value( $value )
+Escape <tt>$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 422: / Line 695: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_insert_quoted -->
+<!-- Pod2Wiki=item_quote_value -->
-====$success = $db-&gt;insert_quoted( $table, $columns, @qvalues )====
+====quote_value====
+ $str = $db-&gt;quote_value( $value )
+Return a quoted version of <tt>$value</tt>. To quote a <tt>LIKE</tt> value  you should use:
+ $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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-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.
-Values will NOT be quoted before insertion - care must be exercised!
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_quote_int -->
+====quote_int====
+ $str = $db-&gt;quote_int( $value )
+Return a quoted integer for <tt>$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 436: / Line 723: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_delete_from -->
+<!-- Pod2Wiki=item_quote_binary -->
-====$success = $db-&gt;delete_from( $table, $columns, @values )====
+====quote_binary====
+ $str = $db-&gt;quote_binary( $bytes )
+Some databases (Oracle/PostgreSQL) require transforms of binary data  to work correctly.
+This method should be called on data <tt>$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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-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.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_quote_ordervalue -->
+====quote_ordervalue====
-If you want to clear a table completely use clear_table().
+ $str = $db-&gt;quote_ordervalue( $field, $value )
+Some databases (Oracle) can't order by <tt>CLOB</tt>s so need special  treatment when creating the ordervalues tables. This method allows any  fixing-up required for string data <tt>$value</tt> for <tt>$field</tt> before it's  inserted.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 450: / Line 751: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_add_record -->
+<!-- Pod2Wiki=item_quote_identifier -->
-====$success = $db-&gt;add_record( $dataset, $data )====
+====quote_identifier====
-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.
+ $str = $db-&gt;quote_identifier( @parts )
+Quote a database identifier (e.g. table names). Multiple <tt>@parts</tt>  will be joined by dots (<tt>.</tt>).
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 462: / Line 764: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prep_int -->
+<!-- Pod2Wiki=item_prepare_regexp -->
-====$mungedvalue = EPrints::Database::prep_int( $value )====
+====prepare_regexp====
-Escape a numerical value for SQL. undef becomes NULL. Anything else becomes a number (zero if needed).
+ $sql = $db-&gt;prepare_regexp( $col, $value )
+The syntax used for regular expressions varies across databases. This  method takes two quoted string and returns a SQL expression that will  apply the quoted regexp <tt>$value</tt> to the quoted column <tt>$col</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 474: / Line 777: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prep_value -->
+<!-- Pod2Wiki=item_sql_as -->
-====$mungedvalue = EPrints::Database::prep_value( $value )====
+====sql_as====
-Escape a value for SQL. Modify value such that " becomes \" and \  becomes \\ and ' becomes \'
+ $sql = $db-&gt;sql_AS()
+Returns the syntactic glue to use when aliasing. SQL 92 databases will  happily use <tt>AS</tt> but some databases (Oracle) will not accept it.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 486: / Line 790: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prep_like_value -->
+<!-- Pod2Wiki=item_sql_like -->
-====$mungedvalue = EPrints::Database::prep_like_value( $value )====
+====sql_like====
+ $sql = $db-&gt;sql_LIKE()
+Returns the syntactic glue to use when making a case-insensitive  <tt>LIKE</tt>. PostgreSQL requires <tt>ILIKE</tt> while everything else uses  <tt>LIKE</tt> and the column collation.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Escape an value for an SQL like field. In addition to ' " and \ also  escapes % and _
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_counters -->
+===Counters===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 498: / Line 812: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_quote_value -->
+<!-- Pod2Wiki=item_counter_current -->
-====$str = $db-&gt;quote_value( $value )====
+====counter_current====
-Return a quoted value. To quote a 'like' value you should do:
+ $n = $db-&gt;counter_current( $counter )
+Return the value of the previous counter_next on <tt>$counter</tt>.
- my $str = $database-&gt;quote_value( EPrints::Database::prep_like_value( $foo ) . '%' );
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 512: / Line 825: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_quote_int -->
+<!-- Pod2Wiki=item_counter_next -->
-====$str = $db-&gt;quote_int( $value )====
+====counter_next====
-Return a quoted integer value
+ $n = $db-&gt;counter_next( $counter )
+Return the next unused value for the named <tt>$counter</tt>. Returns  <tt>undef</tt> if the <tt>$counter</tt> doesn't exist.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 524: / Line 838: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_quote_binary -->
+<!-- Pod2Wiki=item_counter_minimum -->
-====$str = $db-&gt;quote_binary( $bytes )====
+====counter_minimum====
+ $db-&gt;counter_minimum( $counter, $value )
+Ensure that the <tt>$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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Some databases (PostgreSQL) require weird transforms of binary data to work correctly.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_counter_reset -->
+====counter_reset====
-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}}.
+ $db-&gt;counter_reset( $counter )
+Reset the <tt>$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 538: / Line 864: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_quote_identifier -->
+<!-- Pod2Wiki=item_next_doc_pos -->
-====$str = $db-&gt;quote_identifier( @parts )====
+====next_doc_pos====
-Quote a database identifier (e.g. table names). Multiple @parts will be joined by dot.
+ $n = $db-&gt;next_doc_pos( $eprintid )
+Return the next unused document position for the given <tt>$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 550: / Line 877: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_update -->
+<!-- Pod2Wiki=head_dataset_data -->
-====$success = $db-&gt;update( $dataset, $data, $changed, $insert )====
+===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 -->
-Updates a record in the database with the given $data. Obviously the value of the primary key must be set.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_exists -->
+====exists====
-This also updates the text indexes and the ordering keys.
+ $boolean = $db-&gt;exists( $dataset, $id )
+Return <tt>true</tt> if there exists an [[API:EPrints/DataObj|EPrints::DataObj]] from the  <tt>$dataset</tt> with its primary key set to <tt>$id</tt>. Otherwise, return  <tt>false</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 564: / Line 899: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_remove -->
+<!-- Pod2Wiki=item_add_record -->
-====$success = $db-&gt;remove( $dataset, $id )====
+====add_record====
-Attempts to remove the record with the primary key $id from the  specified dataset.
+ $success = $db-&gt;add_record( $dataset, $data )
+Add the given <tt>$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>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 576: / Line 912: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_counters -->
+<!-- Pod2Wiki=item_remove -->
-====$success = $db-&gt;create_counters====
+====remove====
+ $success = $db-&gt;remove( $dataset, $id )
+Attempts to remove the [[API:EPrints/DataObj|EPrints::DataObj]] with the primary key <tt>$id</tt>  from the specified <tt>$dataset</tt>.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Create the counters used to store the highest current id of eprints, users etc.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_searching_caching_and_object_retrieval -->
+===Searching, caching and object retrieval===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 588: / Line 934: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_counter -->
+<!-- Pod2Wiki=item_cache_exp -->
-====$success = $db-&gt;has_counter( $counter )====
+====cache_exp====
-Returns true if $counter exists.
+ $searchexp = $db-&gt;cache_exp( $cacheid )
+Return the serialised search of a the cached search with <tt>$cacheid</tt>. Return <tt>undef</tt> if the <tt>$cacheid</tt> is invalid or expired.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 600: / Line 947: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_create_counter -->
+<!-- Pod2Wiki=item_cache -->
-====$success = $db-&gt;create_counter( $name )====
+====cache====
+ $cacheid = $db-&gt;cache( $searchexp, $dataset, $srctable, [$order], [$list] )
+Create a cache of the specified search expression from the SQL table <tt>$srctable</tt>.
+If <tt>$order</tt> is set then the cache is ordered by the specified fields.  For example <tt>-year/title</tt> orders by year (descending). Records with  the same year are ordered by title.
+If <tt>$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>.
-Create and initialise to zero a new counter called $name.
+If <tt>$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 612: / Line 966: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_remove_counters -->
+<!-- Pod2Wiki=item_cache_table -->
-====$success = $db-&gt;remove_counters====
+====cache_table====
-Destroy all counters.
+ $tablename = $db-&gt;cache_table( $id )
+Return the name of the SQL table used to store the cache with <tt>$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 624: / Line 979: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_counter -->
+<!-- Pod2Wiki=item_cache_userid -->
-====$success = $db-&gt;drop_counter( $name )====
+====cache_userid====
-Destroy the counter named $name.
+ $userid = $db-&gt;cache_userid( $id )
+Returns the <tt>userid</tt> associated with the cache with <tt>$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 636: / Line 992: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_next_doc_pos -->
+<!-- Pod2Wiki=item_get_cachemap -->
-====$n = $db-&gt;next_doc_pos( $eprintid )====
+====get_cachemap====
-Return the next unused document pos for the given eprintid.
+ $cachemap = $db-&gt;get_cachemap( $id )
+Return the cachemap with $&lt;id&gt;.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 648: / Line 1,005: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_current -->
+<!-- Pod2Wiki=item_search -->
-====$n = $db-&gt;counter_current( $counter )====
+====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.
-Return the value of the previous counter_next on $counter.
+If no <tt>$main_table_alias</tt> is specified then <tt>M</tt> is assumed.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 660: / Line 1,020: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_next -->
+<!-- Pod2Wiki=item_drop_cache -->
-====$n = $db-&gt;counter_next( $counter )====
+====drop_cache====
-Return the next unused value for the named counter. Returns undef if  the counter doesn't exist.
+ $db-&gt;drop_cache( $id )
+Remove the cached search with the given <tt>$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 672: / Line 1,033: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_minimum -->
+<!-- Pod2Wiki=item_from_cache -->
-====$db-&gt;counter_minimum( $counter, $value )====
+====from_cache====
+ $items = $db-&gt;from_cache( $dataset, $cacheid, [ $offset, $count, $justids ] )
+Return a reference to an array containing all the items from the given  <tt>$dataset</tt> that have IDs in the cache specified by <tt>$cacheid</tt>. The  cache may be specified either by ID or serialised search expression.
+<tt>$offset</tt> is an offset from the start of the cache and <tt>$count</tt> is  the number of records to return.
-Ensure that the counter is set no lower than $value. This is used when importing eprints which may not be in scrict sequence.
+If <tt>$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 684: / Line 1,050: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_counter_reset -->
+<!-- Pod2Wiki=item_drop_orphan_cache_tables -->
-====$db-&gt;counter_reset( $counter )====
+====drop_orphan_cache_tables====
-Reset the counter. Use with caution.
+ $c = $db-&gt;drop_orphan_cache_tables
+Drop tables called <tt>cacheXXX</tt> where <tt>XXX</tt> is an integer. Returns the  number of cache tables dropped.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 696: / Line 1,063: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_cache_exp -->
+<!-- Pod2Wiki=item_get_single -->
-====$searchexp = $db-&gt;cache_exp( $cacheid )====
+====get_single====
-Return the serialised Search of a the cached search with id $cacheid. Return undef if the id is invalid or expired.
+ $obj = $db-&gt;get_single( $dataset, $id )
+Return a single &lt;EPrints::DataObj&gt; from the given <tt>$dataset</tt> with primary key set to <tt>$id</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 708: / Line 1,076: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_cache -->
+<!-- Pod2Wiki=item_get_all -->
-====$cacheid = $db-&gt;cache( $searchexp, $dataset, $srctable, [$order], [$list] )====
+====get_all====
-Create a cache of the specified search expression from the SQL table $srctable.
+ $items = $db-&gt;get_all( $dataset )
+Returns a reference to an array with all the &lt;EPrints::DataObj&gt;s from  the given <tt>$dataset</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.
+<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 -->
-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.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_get_cache_ids -->
+====get_cache_ids====
+ @ids = $db-&gt;get_cache_ids( $dataset, $cachemap, $offset, $count )
+Returns a list of <tt>$count</tt> IDs from <tt>$cache_id</tt> starting at  <tt>$offset</tt> and in the order in the <tt>$cachemap</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 726: / Line 1,102: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_cache_table -->
+<!-- Pod2Wiki=item_get_dataobjs -->
-====$tablename = $db-&gt;cache_table( $id )====
+====get_dataobjs====
-Return the SQL table used to store the cache with id $id.
+ @dataobjs = $db-&gt;get_dataobjs( $dataset, [ $id, $id, ... ] )
+Retrieves the records in <tt>$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 738: / Line 1,115: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_index_ids -->
+<!-- Pod2Wiki=item_get_values -->
-====$ids = $db-&gt;get_index_ids( $table, $condition )====
+====get_values====
-Return a reference to an array of the distinct primary keys from the given SQL table which match the specified condition.
+ $values = $db-&gt;get_values( $field, $dataset )
+Return a reference to an array of all the distinct values of the  [[API:EPrints/MetaField|EPrints::MetaField]] <tt>$field</tt> for the <tt>$dataset</tt> specified.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 750: / Line 1,128: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_search -->
+<!-- Pod2Wiki=item_sort_values -->
-====$ids = $db-&gt;search( $keyfield, $tables, $conditions, [$main_table_alias] )====
+====sort_values====
-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.
+ $values = $db-&gt;sort_values( $field, $values, [ $langid ] )
+Sorts and returns the list of <tt>$values</tt> using the database.
-If no table alias is passed then M is assumed.
+<tt>$field</tt> is used to get the order value for each value. <tt>$langid</tt>  (or $session-&gt;get_langid if unset) is used to determine the database  collation to use when sorting the resulting order values.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 764: / Line 1,143: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_cache -->
+<!-- Pod2Wiki=item_get_ids_by_field_values -->
-====$db-&gt;drop_cache( $id )====
+====get_ids_by_field_values====
-Remove the cached search with the given id.
+ $ids = $db-&gt;get_ids_by_field_values( $field, $dataset, [ %opts ] )
+Return a reference to a hash table where the keys are specified  <tt>$datasets</tt>'s <tt>$field</tt> value IDs and the values are references to  arrays of IDs.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 776: / Line 1,156: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_count_table -->
+<!-- Pod2Wiki=item_dequeue_events -->
-====$n = $db-&gt;count_table( $tablename )====
+====dequeue_events====
-Return the number of rows in the specified SQL table.
+ @events = $db-&gt;dequeue_events( $n )
+Attempt to dequeue upto <tt>$n</tt> events. May return between <tt>0</tt> and  <tt>$n</tt> events depending on parallel processes and how many events are  remaining in the queue.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 788: / Line 1,169: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_from_cache -->
+<!-- Pod2Wiki=item_ci_lookup -->
-====$foo = $db-&gt;from_cache( $dataset, $cacheid, [$offset], [$count], [$justids] )====
+====ci_lookup====
-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.
+ $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>$field</tt>.
-$offset is an offset from the start of the cache and $count is the number of records to return.
+<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 -->
-If $justids is true then it returns just an ref to an array of the record ids, not the objects.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_password_validation_and_secret_fields -->
+===Password Validation and Secret Fields===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 804: / Line 1,191: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_orphan_cache_tables -->
+<!-- Pod2Wiki=item_valid_login -->
-====$c = $db-&gt;drop_orphan_cache_tables====
+====valid_login====
-Drop tables called "cacheXXX" where XXX is an integer. Returns the number of tables dropped.
+ $db-&gt;valid_login( $username, $password )
+Returns whether the clear-text <tt>$password</tt> matches the stored crypted  password for the <tt>$username</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 816: / Line 1,204: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_single -->
+<!-- Pod2Wiki=item_secret_matches -->
-====$obj = $db-&gt;get_single( $dataset, $id )====
+====secret_matches====
+ $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>$callback</tt> function.
-Return a single item from the given dataset. The one with the specified id.
+If not set, <tt>$callback</tt> defaults to [[API:EPrints/Utils#crypt_equals|EPrints::Utils#crypt_equals]].
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 828: / Line 1,219: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_all -->
+<!-- Pod2Wiki=item_is_secret_set -->
-====$items = $db-&gt;get_all( $dataset )====
+====is_secret_set====
+ $boolean = $db-&gt;is_secret_set( $dataobj, $fieldname )
+Returns a boolean for whether the secret <tt>$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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Returns a reference to an array with all the items from the given dataset.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_database_schema_manipulation -->
+===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>
@@ Line 840: / Line 1,241: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_cache_ids -->
+<!-- Pod2Wiki=item_has_sequence -->
-====@ids = $db-&gt;get_cache_ids( $dataset, $cachemap, $offset, $count )====
+====has_sequence====
-Returns a list of $count ids from $cache_id starting at $offset and in the order in the cachemap.
+ $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%; '>
@@ Line 852: / Line 1,254: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_dataobjs -->
+<!-- Pod2Wiki=item_create_sequence -->
-====@dataobjs = $db-&gt;get_dataobjs( $dataset [, $id [, $id ] ] )====
+====create_sequence====
-Retrieves the records in $dataset with the given $id(s). If an $id doesn't exist in the database it will be ignored.
+ $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 864: / Line 1,267: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_values -->
+<!-- Pod2Wiki=item_drop_sequence -->
-====$foo = $db-&gt;get_values( $field, $dataset )====
+====drop_sequence====
-Return a reference to an array of all the distinct values of the  EPrints::MetaField specified.
+ $success = $db-&gt;drop_sequence( $name )
+Deletes a sequence object with <tt>$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 876: / Line 1,280: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_sort_values -->
+<!-- Pod2Wiki=item_has_column -->
-====$values = $db-&gt;sort_values( $field, $values [, $langid ] )====
+====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 -->
-ALPHA!!! Liable to API change!!!
-Sorts and returns the list of $values using the database.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_drop_column -->
+====drop_column====
-$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.
+ $success = $db-&gt;drop_column( $table, $column )
+Drops the named <tt>$column</tt> from the named <tt>$table</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 892: / Line 1,306: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_ids_by_field_values -->
+<!-- Pod2Wiki=item_get_primary_key -->
-====$ids = $db-&gt;get_ids_by_field_values( $field, $dataset [ %opts ] )====
+====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>.
-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.
+Returns an empty list if no primary key 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 904: / Line 1,321: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_do -->
+<!-- Pod2Wiki=item_index_name -->
-====$success = $db-&gt;do( $sql )====
+====index_name====
+ $name = $db-&gt;index_name( $table, @cols )
+Returns the name of the first index that starts with named columns  <tt>@cols</tt> in the named <tt>$table</tt>.
-Execute the given SQL.
+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 916: / Line 1,336: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prepare -->
+<!-- Pod2Wiki=item_get_index_ids -->
-====$sth = $db-&gt;prepare( $sql )====
+====get_index_ids====
-Prepare the given $sql and return a handle on it.
+ $ids = $db-&gt;get_index_ids( $table, $condition )
+Return a reference to an array of the distinct primary keys from the named SQL <tt>$table</tt> which match the specified <tt>$condition</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 928: / Line 1,349: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prepare_select -->
+<!-- Pod2Wiki=item_create_index -->
-====$sth = $db-&gt;prepare_select( $sql [, %options ] )====
+====create_index====
-Prepare a SELECT statement $sql and return a handle to it. After preparing a statement use execute() to execute it.
+ $success = $db-&gt;create_index( $table, @columns )
+Creates an index over <tt>@columns</tt> for named <tt>$table</tt>. Returns <tt>true</tt>  on success, <tt>false</tt> otherwise.
-The LIMIT SQL keyword is not universally supported, to specify a LIMIT you must use the '''limit''' option.
+<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 -->
-Options:
-  limit - limit the number of rows returned
+<!-- Pod2Wiki= -->
-  offset - return '''limit''' number of rows after offset
+</div>
+<!-- Pod2Wiki=item_create_unique_index -->
+====create_unique_index====
+ $success = $db-&gt;create_unique_index( $tablename, @columns )
+Creates a unique index over <tt>@columns</tt> for named <tt>$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%; '>
 <span style='display:none'>User Comments</span>
@@ Line 947: / Line 1,375: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_execute -->
+<!-- Pod2Wiki=item_create_foreign_key -->
-====$success = $db-&gt;execute( $sth, $sql )====
+====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>.
-Execute the SQL prepared earlier. $sql is only passed in for debugging purposes.
+This will cause records in <tt>$table</tt> to be deleted if the equivalent  record is deleted from <tt>$main_table</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 959: / Line 1,390: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_dataset -->
+<!-- Pod2Wiki=item_get_tables -->
-====$db-&gt;has_dataset( $dataset )====
+====get_tables====
-Returns true if $dataset exists in the database or has no database tables.
+ @tables = $db-&gt;get_tables( [ $dbname ] )
+Returns a list of all the tables in the database.
-This does not check that all fields are configured - see has_field().
+<tt>$dbname</tt> specifies a particular database name of current connection has access to more than one 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 973: / Line 1,405: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_field -->
+<!-- Pod2Wiki=item_has_table -->
-====$db-&gt;has_field( $dataset, $field )====
+====has_table====
-Returns true if $field is in the database for $dataset.
+ $boolean = $db-&gt;has_table( $tablename )
+Returns boolean dependent on whether a table of the <tt>$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%; '>
@@ Line 985: / Line 1,418: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_add_field -->
+<!-- Pod2Wiki=item_create_table -->
-====$db-&gt;add_field( $dataset, $field [, $force ] )====
+====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.
-Add $field to $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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-If $force is true will modify/replace an existing column (use with care!).
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=item_drop_table -->
+====drop_table====
+ $db-&gt;drop_table( @tables )
+Delete the named <tt>@tables</tt>. Use with caution!
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 999: / Line 1,446: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_remove_field -->
+<!-- Pod2Wiki=item_rename_table -->
-====$db-&gt;remove_field( $dataset, $field )====
+====rename_table====
-Remove $field from $dataset's tables.
+ $db-&gt;rename_table( $table_from, $table_to )
+Renames the table named <tt>$table_from</tt> to <tt>$table_to</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,011: / Line 1,459: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_rename_field -->
+<!-- Pod2Wiki=item_swap_table -->
-====$ok = $db-&gt;rename_field( $dataset, $field, $old_name )====
+====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.
-Rename a $field in the database from it's old name $old_name.
+<div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
-Returns true if the field was successfully renamed.
+<!-- Pod2Wiki= -->
+</div>
+<!-- Pod2Wiki=head_eprints_schema_manipulation -->
+===EPrints Schema Manipulation===
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
 <span style='display:none'>User Comments</span>
@@ Line 1,025: / Line 1,481: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_exists -->
+<!-- Pod2Wiki=item_create_archive_tables -->
-====$boolean = $db-&gt;exists( $dataset, $id )====
+====create_archive_tables====
-Return true if a record with the given primary key exists in the dataset, otherwise false.
+ $success = $db-&gt;create_archive_tables()
+Create all the SQL tables for all datasets.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,037: / Line 1,494: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_set_debug -->
+<!-- Pod2Wiki=item_drop_archive_tables -->
-====$db-&gt;set_debug( $boolean )====
+====drop_archive_tables====
-Set the SQL debug mode to true or false.
+ $db-&gt;drop_archive_tables()
+Destroy all tables used by EPrints in the database.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,050: / Line 1,508: @@
 </div>
 <!-- Pod2Wiki=item_create_version_table -->
-====$db-&gt;create_version_table====
+====create_version_table====
-Make the version table (and set the only value to be the current version of eprints).
+ $db-&gt;create_version_table
+Make the version table (and set the only value to be the current version of EPrints).
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,062: / Line 1,521: @@
 </div>
 <!-- Pod2Wiki=item_drop_version_table -->
-====$db-&gt;drop_version_table====
+====drop_version_table====
+ $db-&gt;drop_version_table
 Drop the version table.
@@ Line 1,073: / Line 1,533: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_set_version -->
+<!-- Pod2Wiki=item_has_dataset -->
-====$db-&gt;set_version( $versionid );====
+====has_dataset====
+ $db-&gt;has_dataset( $dataset )
+Returns <tt>true</tt> if <tt>$dataset</tt> exists in the database and has all  expected tables including ordervalues and index tables.
-Set the version id table in the SQL database to the given value (used by the upgrade script).
+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 1,085: / Line 1,548: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_table -->
+<!-- Pod2Wiki=item_has_dataset_index_tables -->
-====$boolean = $db-&gt;has_table( $tablename )====
+====has_dataset_index_tables====
-Return true if a table of the given name exists in the database.
+ $db-&gt;has_dataset_index_tables( $dataset )
+Returns <tt>true</tt> if index tables for <tt>$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 1,097: / Line 1,561: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_has_column -->
+<!-- Pod2Wiki=item_create_dataset_tables -->
-====$boolean = $db-&gt;has_column( $tablename, $columnname )====
+====create_dataset_tables====
-Return true if the a table of the given name has a column named $columnname in the database.
+ $success = $db-&gt;create_dataset_tables( $dataset )
+Creates all the SQL tables for the specified <tt>$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 1,109: / Line 1,574: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_index_name -->
+<!-- Pod2Wiki=item_drop_dataset_tables -->
-====$name = $db-&gt;index_name( $table, @columns )====
+====drop_dataset_tables====
-Returns the name of the first index that starts with @columns on the $table table.
-Returns undef if no index exists.
+ $db-&gt;drop_dataset_tables( $dataset )
+Drops all the SQL tables for the specified <tt>$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 1,123: / Line 1,587: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_drop_table -->
+<!-- Pod2Wiki=item_create_dataset_index_tables -->
-====$db-&gt;drop_table( $tablename )====
+====create_dataset_index_tables====
-Delete the named table. Use with caution!
+ $success = $db-&gt;create_dataset_index_tables( $dataset )
+Creates all the index tables for the specified <tt>$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 1,135: / Line 1,600: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_clear_table -->
+<!-- Pod2Wiki=item_create_dataset_ordervalues_tables -->
-====$db-&gt;clear_table( $tablename )====
+====create_dataset_ordervalues_tables====
-Clears all records from the given table, use with caution!
+ $success = $db-&gt;create_dataset_ordervalues_tables( $dataset )
+Creates all the ordervalues tables for the specified <tt>$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 1,147: / Line 1,613: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_rename_table -->
+<!-- Pod2Wiki=item_has_field -->
-====$db-&gt;rename_table( $tablename, $newtablename )====
+====has_field====
-Renames the table from the old name to the new one.
+ $db-&gt;has_field( $dataset, $field )
+Returns <tt>true</tt> if <tt>$field</tt> is in the database for <tt>$dataset</tt>.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,159: / Line 1,626: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_swap_table -->
+<!-- Pod2Wiki=item_add_field -->
-====$db-&gt;swap_table( $table_a, $table_b )====
+====add_field====
+ $db-&gt;add_field( $dataset, $field, [ $force ] )
+Add <tt>$field</tt> to <tt>$dataset</tt>'s tables.
-Swap table a and table b.
+If <tt>$force</tt> is <tt>true</tt> modify/replace an existing column. Use with  care!
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,171: / Line 1,641: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_tables -->
+<!-- Pod2Wiki=item_remove_field -->
-====@tables = $db-&gt;get_tables====
+====remove_field====
-Return a list of all the tables in the database.
+ $db-&gt;remove_field( $dataset, $field )
+Remove <tt>$field</tt> from <tt>$dataset</tt>'s tables.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,183: / Line 1,654: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_version -->
+<!-- Pod2Wiki=item_rename_field -->
-====$version = $db-&gt;get_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>.
-Return the version of eprints which the database is compatable with or undef if unknown (before v2.1).
+Returns <tt>true</tt> if the <tt>$field</tt> is successfully renamed.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,195: / Line 1,669: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_is_latest_version -->
+<!-- Pod2Wiki=item_create_counters -->
-====$boolean = $db-&gt;is_latest_version====
+====create_counters====
-Return true if the SQL tables are in the correct configuration for this edition of eprints. Otherwise false.
+ $success = $db-&gt;create_counters
+Create the counters used to store the highest current ID of eprints, users, etc.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,207: / Line 1,682: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_valid_login -->
+<!-- Pod2Wiki=item_has_counter -->
-====$db-&gt;valid_login( $username, $password )====
+====has_counter====
-Returns whether the clear-text $password matches the stored crypted password for $username.
+ $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 1,219: / Line 1,695: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_server_version -->
+<!-- Pod2Wiki=item_create_counter -->
-====$version = $db-&gt;get_server_version====
+====create_counter====
-Return the database server version.
+ $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%; '>
@@ Line 1,231: / Line 1,708: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_default_charset -->
+<!-- Pod2Wiki=item_remove_counters -->
-====$charset = $db-&gt;get_default_charset( LANGUAGE )====
+====remove_counters====
-Return the character set to use for LANGUAGE.
+ $success = $db-&gt;remove_counters
+Destroy all counters.
-Returns undef if character sets are unsupported.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,245: / Line 1,721: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_default_collation -->
+<!-- Pod2Wiki=item_drop_counter -->
-====$collation = $db-&gt;get_default_collation( LANGUAGE )====
+====drop_counter====
+ $success = $db-&gt;drop_counter( $name )
+Destroy the counter named <tt>$name</tt>.
-Return the collation to use for LANGUAGE.
+<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 collation is unsupported.
+<!-- 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 1,259: / Line 1,743: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_get_driver_name -->
+<!-- Pod2Wiki=item_save_user_message -->
-====$driver = $db-&gt;get_driver_name====
+====save_user_message====
-Return the database driver name.
+ $message = $db-&gt;save_user_message( $userid, $m_type, $dom_m_data )
+Save user message provided in XML DOM object <tt>$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.
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@@ Line 1,271: / Line 1,756: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_dequeue_events -->
+<!-- Pod2Wiki=item_get_user_messages -->
-====@events = $db-&gt;dequeue_events( $n )====
+====get_user_messages====
-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.
+ @messages = $db-&gt;get_user_messages( $userid, %opts )
+Get the messages for a user with ID <tt>$userid</tt> and clear messages if <tt>$opt{clear}</tt> is set.
 <div style='background-color: #e8e8f; margin: 0.5em 0em 1em 0em; border: solid 1px #cce;  padding: 0em 1em 0em 1em; font-size: 80%; '>
@@ Line 1,283: / Line 1,769: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_prepare_regexp -->
+<!-- Pod2Wiki=item_clear_user_messages -->
-====$sql = $db-&gt;prepare_regexp( $quoted_column, $quoted_value )====
+====clear_user_messages====
-The syntax used for regular expressions varies across databases. This method takes two '''quoted''' values and returns a SQL expression that will apply the regexp ($quoted_value) to the column ($quoted_column).
+ $db-&gt;clear_user_messages( $userid )
+Clear all messages for user with ID <tt>$userid</tt>.
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@@ Line 1,295: / Line 1,782: @@
 <!-- Pod2Wiki= -->
 </div>
-<!-- Pod2Wiki=item_alias_glue -->
+<!-- Pod2Wiki=head_see_also -->
-====$glue = $db-&gt;alias_glue()====
+==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]].
-Returns the syntactic glue to use when aliasing. SQL 92 DBs will happilly use " AS " but some DBs (Oracle!) won't 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%; '>
+<span style='display:none'>User Comments</span>
+<!-- Edit below this comment -->
+<!-- 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