NAME

DBIx::EnumConstraints - generates enum-like SQL constraints.

SYNOPSIS

  use DBIx::EnumConstraints;

  my $ec = DBIx::EnumConstraints->new({
                table => 'the_table'
                , name => 'kind', fields => [ [ 'a', 'b' ]
                                        , [ 'b' ] ]
  });

DESCRIPTION

This module generates SQL statements for enforcing enum semantics on the database columns.

Enum columns is the column which can get one of 1 .. k values. For each of those values there are other columns which should or should not be null.

For example in the SYNOPSIS above, when kind column is 1 the row should have both of a and b columns not null. When kind column is 2 the row should have a but no b columns.

CONSTRUCTORS

$class->new($args)

$args should be HASH reference containing the following parameters:

table

The table for which to generate the constraints.

name

The name of the enum.

fields

Array of arrays describing columns dependent on the enum. Each row is index is the possible value of enum minus 1 (e.g. row number 1 is for enum value 2).

The items are column names. There is a possibility to mark optional columns by using trailing ? (e.g. b? denotes an optional b field.

column_groups

Hash of columns dependent on other columns. E.g. a => [ 'b', 'c' ] means that when a is present b, c columns should be present as well.

The key column should be given in fields parameter above.

METHODS

$self->for_each_kind($callback)

Runs $callback over registered enum states. For each state passes state index, fields which are in the state and fields which are out of the state.

The fields are passed as ARRAY references.

$self->make_constraints

Generates suitable PostgreSQL constraints using the fields.

Also generates drop plpgsql function to automate dropping of the constraints.

$self->load_fields_from_db($dbh)

Loads fields configuration from the database using current constraints.

AUTHOR

        Boris Sukholitko
        CPAN ID: BOSU
        
        boriss@gmail.com
        

COPYRIGHT

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

The full text of the license can be found in the LICENSE file included with this module.