NAME

Tree::Persist::DB::SelfReferential - A handler for Tree persistence

SYNOPSIS

See "SYNOPSIS" in Tree::Persist or scripts/xml.demo.pl for sample code.

DESCRIPTION

This module is a plugin for Tree::Persist to store a Tree to a self-referential DB table. This is where a table contains an id column for the row and a parent_id column that refers back to another row's id (which is the parent row).

This is the simplest way to store a tree datastructure in a database, but it has performance penalties.

PARAMETERS

Parameters are used in the call to "connect({%opts})" in Tree::Persist or "create_datastore({%opts})" in Tree::Persist.

In addition to any parameters required by its parent Tree::Persist::DB, the following parameters are used by connect() or create_datastore():

• id (required)

  This is the id for the root node of the tree. By specifying this, you can both store more that one tree in a table as well as only load a subtree.

• id_col (optional)

  This is the column name for the id field. It defaults to "id".

• parent_id_col (optional)

  This is the column name for the parent_id field. It defaults to "parent_id".

• value_col (optional)

  This is the column name for the value field. It defaults to "value".

• class_col (optional)

  This is the column name for the class field.

Methods

Tree::Persist::DB::SelfReferential is a sub-class of Tree::Persist::DB, and inherits all its methods.

TODO

• Provide for a way to default the class to 'Tree' if no class_col is provided. Also, allow for the classname to be passed into the constructor.

CODE COVERAGE

Please see the relevant section of Tree::Persist.

SUPPORT

Please see the relevant section of Tree::Persist.

AUTHORS

Rob Kinyon <rob.kinyon@iinteractive.com>

Stevan Little <stevan.little@iinteractive.com>

Thanks to Infinity Interactive for generously donating our time.

Co-maintenance since V 1.01 is by Ron Savage <rsavage@cpan.org>. Uses of 'I' in previous versions is not me, but will be hereafter.

COPYRIGHT AND LICENSE

Copyright 2004, 2005 by Infinity Interactive, Inc.

http://www.iinteractive.com

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