API:EPrints/DataSet

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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::DataSet - a dataset is a set of records in the eprints system with the same metadata.

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SYNOPSIS

 my $dataset = $repository->get_dataset( "inbox" );
 
 print sprintf("There are %d records in the inbox\n",
   $dataset->count);
 
 $string = $dataset->base_id; # eprint
 $string = $dataset->id; # inbox
 
 $dataobj = $dataset->create_dataobj( $data );
 $user = $dataset->dataobj( 23 );
 
 $search = $dataset->prepare_search( %options );
 $list = $dataset->search( %options ); # prepare_search( %options )->execute
 $list = $dataset->search; # match ALL
 
 $metafield = $dataset->field( $fieldname );
 $metafield = $dataset->key_field;
 @metafields = $dataset->fields; 
 
 $dataset->search->map( sub {}, $ctx );
 $n = $dataset->search->count; 
 $ids = $dataset->search->ids;
 $list = $dataset->list( \@ids );
 

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DESCRIPTION

This module describes an EPrint dataset.

A repository has several datasets that make up the repository's database. The list of dataset ids can be obtained from the repository object (see EPrints::Repository).

A normal dataset (eg. "user") has a package associated with it (eg. EPrints::DataObj::User) which must be a subclass of EPrints::DataObj and a number of SQL tables which are prefixed with the dataset name. Most datasets also have a set of associated EPrints::MetaField's which may be optional or compulsary depending on the type eg. books have editors but posters don't but they are both EPrints.

The fields contained in a dataset are defined by the data object and by any additional fields defined in cfg.d. Some datasets don't have any fields.

Some datasets are "virtual" datasets made from others. Examples include "inbox", "archive", "buffer" and "retired" which are all virtual datasets of of the "eprint" dataset. That is to say "inbox" is a subset of "eprint" and by inference contains EPrints::DataObj::EPrints. You can define your own virtual datasets which opperate on existing datasets.

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Object Methods

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$id = $ds->base_id

 $ds = $repo->dataset( "inbox" );
 $id = $ds->base_id; # returns "eprint"
 

Returns the identifier of the base dataset for this dataset (same as /id unless this dataset is virtual).

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$metafield = $ds->field( $fieldname )

Returns the EPrints::MetaField from this dataset with the given name, or undef.

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$id = $ds->id

Return the id of this dataset.

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$n = $ds->count( $session )

Return the number of records in this dataset.

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@fields = $ds->fields

Returns a list of the EPrints::MetaFields belonging to this dataset.

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$field = $ds->key_field

Return the EPrints::MetaField representing the primary key field.

Always the first field.

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$dataobj = $ds->make_dataobj( $epdata )

Return an object of the class associated with this dataset, always a subclass of EPrints::DataObj.

$epdata is a hash of values for fields in this dataset.

Returns $epdata if no class is associated with this dataset.

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$obj = $ds->create_dataobj( $data )

Returns a new object in this dataset based on $data or undef on failure.

If $data describes sub-objects then those will also be created.

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$dataobj = $ds->dataobj( $id )

Returns the object from this dataset with the given id, or undefined.

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$repository = $ds->repository

Returns the EPrints::Repository to which this dataset belongs.

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$searchexp = $ds->prepare_search( %options )

Returns a EPrints::Search for this dataset with %options.

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$list = $ds->search( %options )

Short-cut to /prepare_search( %options )->execute.

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$list = $ds->list( $ids )

Returns a EPrints::List for this dataset for the given $ids list.

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