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Jifty::DBI::Record::AutoIncremented
Autoincrement the id field of a Jifty::DBI::Record

Jifty::DBI::Record::AutoIncremented - Autoincrement the id field of a Jifty::DBI::Record


NAME

Jifty::DBI::Record::AutoIncremented - Autoincrement the id field of a Jifty::DBI::Record


VERSION

$Id: AutoIncremented.pm,v 1.1 2006/07/28 08:22:22 erwan Exp $


SYNOPSIS

Assuming you have a table containing objects of the type MyRecord:


    package MyRecord::Schema;

    use Jifty::DBI::Schema;

    column name => type is 'text';

    column year => type is 'integer';

This table has 3 columns: 'name', 'year' and 'id' that was auto-magically added by Jifty and is the table's primary key. 'id' is an integer, incremented by 1 upon each insertion of a new row in the table, and starting at 1.

Declare your own Record class inheriting from Jifty::DBI::Record::AutoIncremented:


    package MyRecord;

    use base qw(Jifty::DBI::Record::AutoIncremented);

    sub _init { 

        # some stuff...

    }

Now, creating instances of MyRecord will have each object's 'id' field automatically incremented to the next available id before insertion.


   my $mr = MyRecord->new();

   $mr->create(name => 'first hit', year => 2005);  # get's id=1

   # print 1

   print "created a row with id: ".$mr->maximum_value_of()."\n";

   $mr->create(name => 'future hit', year => 2012);  # get's id=2

   $mr->load_by_cols(id => $mr->maximum_value_of);   # load this entry


DESCRIPTION

Jifty::DBI::Record::AutoIncremented is a subclass of Jifty::DBI::Record that can be used instead of Jifty::DBI::Record and that transparently increments a record's id field upon each create/insert.

Some databases


INTERFACE

Jifty::DBI::Record::AutoIncremented adds 2 methods to Jifty::DBI::Record:

$record->maximum_value_of($column)
Return the current maximum value of the given column in the database. If $column is omitted, 'id' is assumed as the default column. If the table has no entries, undef is returned.

This is particularly usefull after calling create to learn the id of the inserted row.

$record->b<before_create>
A callback method called by Jifty::DBI::Record->create. Sets the new record'd id field to maximum_value_of('id'). If you define your own before_create callback in a subclass of Jifty::DBI::Record::AutoIncremented, don't forget to call this before_create from it.


BUGS AND LIMITATIONS

No bugs found so far. Jifty::DBI::Record::AutoIncremented queries the database for the current maximum value of the id column upon each insert, which is not so optimal...


SEE ALSO

See Jifty::DBI::Record.


COPYRIGHT AND LICENSE

Copyright (C) 2005 by Erwan Lemonnier <erwan@cpan.org>

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.


DISCLAIMER OF WARRANTY

Blablabla not my fault blablabla your responsibility.

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