1Class::DBI::RelationshiUps(e3r)Contributed Perl DocumentCaltaisosn::DBI::Relationship(3)
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NAME

6       Class::DBI::Relationship - base class for Relationships
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DESCRIPTION

9       A Class::DBI class represents a database table. But merely being able
10       to represent single tables isn't really that useful - databases are all
11       about relationships.
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13       So, Class::DBI provides a variety of Relationship models to represent
14       common database occurences (HasA, HasMany and MightHave), and provides
15       a way to add others.
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SUBCLASSING

18       Relationships should inherit from Class::DBI::Relationship, and provide
19       a variety of methods to represent the relationship. For examples of how
20       these are used see Class::DBI::Relationship::HasA,
21       Class::DBI::Relationship::HasMany and
22       Class::DBI::Relationship::MightHave.
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24   remap_arguments
25               sub remap_arguments {
26                       my $self = shift;
27                       # process @_;
28                       return ($class, accessor, $foreign_class, $args)
29               }
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31       Subclasses should define a 'remap_arguments' method that takes the
32       arguments with which your relationship method will be called, and
33       transforms them into the structure that the Relationship modules
34       requires.  If this method is not provided, then it is assumed that your
35       method will be called with these 3 arguments in this order.
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37       This should return a list of 4 items:
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39       class
40           The Class::DBI subclass to which this relationship applies. This
41           will be passed in to you from the caller who actually set up the
42           relationship, and is available for you to call methods on whilst
43           performing this mapping. You should almost never need to change
44           this.
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46           This usually an entire application base class (or Class::DBI
47           itself), but could be a single class wishing to override a default
48           relationship.
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50       accessor
51           The method in the class which will provide access to the results of
52           the relationship.
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54       foreign_class
55           The class for the table with which the class has a relationship.
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57       args
58           Any additional args that your relationship requires.  It is
59           recommended that you use this as a hashref to store any extra
60           information your relationship needs rather than adding extra
61           accessors, as this information will all be stored in the
62           'meta_info'.
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64   triggers
65               sub triggers {
66                       return (
67                               before_create => sub { ... },
68                               after_create  => sub { ... },
69                       );
70               }
71
72       Subclasses may define a 'triggers' method that returns a list of
73       triggers that the relationship needs. This method can be omitted if
74       there are no triggers to be set up.
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76   methods
77               sub methods {
78                       return (
79                               method1 => sub { ... },
80                               method2 => sub { ... },
81                       );
82               }
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84       Subclasses may define a 'methods' method that returns a list of methods
85       to facilitate the relationship that should be created in the calling
86       Class::DBI class.  This method can be omitted if there are no methods
87       to be set up.
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91perl v5.28.0                      2005-09-16       Class::DBI::Relationship(3)
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