1Relationship(3) User Contributed Perl Documentation Relationship(3)
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6 Class::DBI::Loader::Relationship - Easier relationship specification in
7 CDBI::Loader
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10 use Class::DBI::Loader::Relationship;
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12 my $loader = Class::DBI::Loader->new( dsn => "mysql:beerdb",
13 namespace => "BeerDB");
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15 Now instead of saying
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17 BeerDB::Brewery->has_many(beers => "BeerDB::Beer");
18 BeerDB::Beer->has_a(brewery => "BeerDB::Brewery");
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20 BeerDB::Handpump->has_a(beer => "BeerDB::Beer");
21 BeerDB::Handpump->has_a(pub => "BeerDB::Pub");
22 BeerDB::Pub->has_many(beers => [ BeerDB::Handpump => 'beer' ]);
23 BeerDB::Beer->has_many(pubs => [ BeerDB::Handpump => 'pub' ]);
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25 Just say
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27 $loader->relationship( "a brewery produces beers" );
28 $loader->relationship( "a pub has beers on handpumps" );
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30 And something like ( upgraded in v1.3 )
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32 MyApp::Page->has_a( author => 'MyApp::User' );
33 MyApp::Page->has_many( revisions => 'MyApp::PageRevision' );
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35 Just say
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37 $loader->relationship( "a page has an user as author" );
38 $loader->relationship( "a page has many page_revisions as revisions" );
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41 This module acts as a mix-in, adding the "relationship" method to
42 "Class::DBI::Loader". Since "Class::DBI::Loader" knows how to map
43 between table names and class names, there ought to be no need to
44 replicate the names.
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46 In addition, it is common (but not universal) to want reverse
47 relationships defined for has-many relationships, and for has-a
48 relationships to be defined for the linkages surrounding a many-to-many
49 table.
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51 The aim of "CDBIL::Relationship" is to simplify the declaration of
52 common database relationships by providing both of these features.
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54 The "relationship" takes a string. It recognises table names (singular
55 or plural, for convenience) and extracts them from the "sentence".
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58 Simon Cozens, "simon@cpan.org"
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60 Chunzi, "chunzi@perlchina.org"
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63 Class::DBI::Loader.
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67perl v5.36.0 2023-01-20 Relationship(3)