API:EPrints/Database

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Contents

NAME

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

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.

The database object is created automatically when you start a new eprints session. To get a handle on it use:

$db = $session->get_repository

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.

Variables that are database quoted are prefixed with 'Q_'.

build_connection_string

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

Build the string to use to connect to the database via DBI. %params must contain dbname, and may also contain dbport, dbhost and dbsock.

new

 $db = EPrints::Database->new( $session )

Create a connection to the database.

connect

 $foo = $db->connect

Connects to the database.

disconnect

 $foo = $db->disconnect

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

error

 $errstr = $db->error

Return a string describing the last SQL error.

begin

 $db->begin

Begin a transaction.

commit

 $db->commit

Commit the previous begun transaction.

rollback

 $db->rollback

Rollback the partially completed transaction.

create_archive_tables

 $success = $db->create_archive_tables

Create all the SQL tables for each dataset.

create_dataset_tables

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

Create all the SQL tables for a single dataset.

drop_dataset_tables

 $db->drop_dataset_tables( $dataset )

Drop all the SQL tables for a single dataset.

create_dataset_index_tables

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

Create all the index tables for a single dataset.

create_dataset_ordervalues_tables

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

Create all the ordervalues tables for a single dataset.

get_column_type

 $real_type = $db->get_column_type( NAME, TYPE, NOT_NULL, [, LENGTH ] )

Returns a column definition for NAME of type TYPE. If NOT_NULL is true the column will be created NOT NULL. For column types that require a length use LENGTH.

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.

Binary data: SQL_VARBINARY(n), SQL_LONGVARBINARY.

Integer data: SQL_TINYINT, SQL_SMALLINT, SQL_INTEGER.

Floating-point data: SQL_REAL, SQL_DOUBLE.

Time data: SQL_DATE, SQL_TIME.

create_table

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

Create the tables used to store metadata for this dataset: the main table and any required for multiple or mulitlang fields.

has_sequence

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

Return true if a sequence of the given name exists in the database.

create_sequence

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

Creates a new sequence object initialised to zero.

drop_sequence

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

Deletes a sequence object.

get_primary_key

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

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

Returns empty list if no primary key exists.

create_index

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

Creates an index over @columns for $tablename. Returns true on success.

create_unique_index

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

Creates a unique index over @columns for $tablename. Returns true on success.

_update

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

UDATES $tablename where $keycols equals $keyvals.

This method is internal.

_update_quoted

 $success = $db->_update_quoted( $tablename, $keycols, $keyvals, $columns, @values )

UDATES $tablename where $keycols equals $keyvals. Won't quote @keyvals or @values before use - use this method with care!

This method is internal.

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.

Values will be quoted before insertion.

insert_quoted

 $success = $db->insert_quoted( $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.

Values will NOT be quoted before insertion - care must be exercised!

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().

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.

prep_int

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

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

prep_value

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

Escape a value for SQL. Modify value such that " becomes \" and \ becomes \\ and ' becomes \'

prep_like_value

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

Escape an value for an SQL like field. In addition to ' " and \ also escapes % and _

quote_value

 $str = EPrints::Database::quote_value( $value )

Return a quoted value. To quote a 'like' value you should do:

my $str = $database->quote_value( EPrints::Database::prep_like_value( $foo ) . '%' );
 

quote_int

 $str = EPrints::Database::quote_int( $value )

Return a quoted integer value

quote_identifier

 $str = EPrints::Database::quote_identifier( @parts )

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

update

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

Updates a record in the database with the given $data. Obviously the value of the primary key must be set.

This also updates the text indexes and the ordering keys.

remove

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

Attempts to remove the record with the primary key $id from the specified dataset.

create_counters

 $success = $db->create_counters

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

has_counter

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

Returns true if $counter exists.

create_counter

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

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

remove_counters

 $success = $db->remove_counters

Destroy all counters.

drop_counter

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

Destroy the counter named $name.

next_doc_pos

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

Return the next unused document pos for the given eprintid.

counter_current

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

Return the value of the previous counter_next on $counter.

counter_next

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

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

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.

counter_reset

 $db->counter_reset( $counter )

Reset the counter. Use with caution.

cache_exp

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

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

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.

cache_table

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

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

create_buffer

 $tablename = $db->create_buffer( $keyname )

Create a temporary table with the given keyname. This table will not be available to other processes and should be disposed of when you've finished with them - MySQL only allows so many temporary tables.

make_buffer

 $id = $db->make_buffer( $keyname, $data )

Create a temporary table and dump the values from the array reference $data into it.

Even in debugging mode it does not mention this SQL as it's very dull.

garbage_collect

 $foo = $db->garbage_collect

Loop through known temporary tables, and remove them.

dispose_buffer

 $db->dispose_buffer( $id )

Remove temporary table with given id. Won't just remove any old table.

get_index_ids

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

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

search

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

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

If no table alias is passed then M is assumed.

drop_cache

 $db->drop_cache( $id )

Remove the cached search with the given id.

count_table

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

Return the number of rows in the specified SQL table.

from_buffer

 $items = $db->from_buffer( $dataset, $buffer, [$offset], [$count], [$justids] )

Return a reference to an array containing all the items from the given dataset that have id's in the specified buffer.

from_cache

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

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

$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 an ref to an array of the record ids, not the objects.

drop_old_caches

 $db->drop_old_caches

Drop all the expired caches.

get_single

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

Return a single item from the given dataset. The one with the specified id.

get_all

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

Returns a reference to an array with all the items from the given dataset.

get_values

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

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

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 field value ids and the value is a reference to an array of ids.

do

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

Execute the given SQL.

prepare

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

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

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.

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

Options:

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

execute

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

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

has_dataset

 $db->has_dataset( $dataset )

Returns true if $dataset exists in the database or has no database tables.

This does not check that all fields are configured - see has_field().

has_field

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

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

add_field

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

Add $field to $dataset's tables.

remove_field

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

Remove $field from $dataset's tables.

exists

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

Return true if a record with the given primary key exists in the dataset, otherwise false.

set_timer

 $db->set_timer( $boolean )

Set the detailed timing option.

set_debug

 $db->set_debug( $boolean )

Set the SQL debug mode to true or false.

create_version_table

 $db->create_version_table

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

set_version

 $db->set_version( $versionid );

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

has_table

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

Return true if the a table of the given name exists in the database.

has_column

 $boolean = $db->has_column( $tablename, $columnname )

Return true if the a table of the given name has a column named $columnname in the database.

install_table

 $db->install_table( $tablename, $newtablename )

Move table $tablename to $newtablename. Erase $newtablename if it exists.

drop_table

 $db->drop_table( $tablename )

Delete the named table. Use with caution!

clear_table

 $db->clear_table( $tablename )

Clears all records from the given table, use with caution!

rename_table

 $db->rename_table( $tablename, $newtablename )

Renames the table from the old name to the new one.

swap_table

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

Swap table a and table b.

get_tables

 @tables = $db->get_tables

Return a list of all the tables in the database.

get_version

 $version = $db->get_version

Return the version of eprints which the database is compatable with or undef if unknown (before v2.1).

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.

valid_login

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

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

index_queue

 $db->index_queue( $datasetid, $objectid, $fieldname [, $fieldname ] );

Queues the field of the specified object to be reindexed.

index_dequeue

 ($datasetid, $objectid, $field) = $db->index_dequeue();

Pops an item off the queue. Returns empty list if nothing left.

Permissions

add_roles

 $db->add_roles( $privilege, $ip_from, $ip_to, @roles )

Add $privilege to @roles, optionally in net space $ip_from to $ip_to.

If $privilege begins with '@' adds @roles to that group.

remove_roles

 $db->remove_roles( $privilege, $ip_from, $ip_to, @roles )

Remove $privilege from @roles, $ip_from and $ip_to are currently ignored, but this behaviour may change in future.

If $privilege beings with '@' removes @roles from that group instead.

get_privileges

 %privs = $db->get_privileges( [$role] )

Return the privileges granted for $role. If $role is undefined returns all set privileges.

Returns a hash:

 role => {
   priv1 => [ ip_from, ip_to ],
   priv2 => [ ip_from, ip_to ],
 }
 

get_groups

 %groups = $db->get_groups( [$role] )

Returns a list of groups that $role belongs to, or all groups if $role is undefined.

Returns a hash:

 role => [ group1, group2, group3 ]
 

get_roles

 @roles = $db->get_roles( $privilege, $remote_ip, @roles )

Get the matching roles for @roles that have $privilege, optionally restricted to $remote_ip.

get_server_version

 $version = $db->get_server_version

Return the database server version.

get_driver_name

 $driver = $db->get_driver_name

Return the database driver name.

UNDOCUMENTED METHODS

Warning These methods were found in the source code but didn't have any POD associated with them. This may be because we haven't got around to documenting them yet or it could be because they are internal to the API and not intended for use by other parts of EPrints.

add_index_to_indextable

cache_userid

clear_user_messages

create_login_tickets_table

get_ticket_userid

get_user_messages

save_user_message

swap_tables

update_ticket_userid