NAME

Handel::Components::Constraints - Column constraints for schemas

SYNOPSIS

    package MySchema::Table;
    use strict;
    use warnings;
    use base qw/DBIx::Class/;
    
    __PACKAGE__->load_components('+Handel::Component::Constraints');
    __PACKAGE__->add_constraint('column', 'Constraint Name' => \&checker);
    
    1;

DESCRIPTION

Handel::Components::Constraints is a simple way to validate column data during inserts/updates using subroutines. It mostly acts as a compatibility layer for subclasses that used add_constraint when Handel used Class::DBI.

There is no real reason to load this component into your schema table classes directly. If you add constraints using Handel::Storage->add_constraint, this component will be loaded into the appropriate schema source class automatically.

METHODS

add_constraint

Arguments: $column, $name, \&sub

Adds a named constraint for the specified column.

    __PACKAGE__->add_constraint('quantity', 'Check Quantity' => \%check_qty);

Note: Always use the real column name in the database, not the accessor alias for the column.

check_constraints

This loops through all of the configured constraints, calling the specified \&sub. Each sub will receive the following arguments:

    sub mysub {
        my ($value, $source, $column, \%data) = @_;
        
        if ($value) {
            return 1;
        } else {
            return 0;
        };
    };

value

The value of the column to be checked.

source

The result object for the row being updated/inserted.

column

The name of the column being checked.

data

A hash reference containing all of the columns and their values. Changing any values in the hash will also change the value inserted/updated in the database.

insert

Calls check_constraints and then inserts the row. See "insert" in DBIx::Class::Row for more information about insert.

update

Calls check_constraints and then updates the row. See "update" in DBIx::Class::Row for more information about update.

AUTHOR

    Christopher H. Laco
    CPAN ID: CLACO
    claco@chrislaco.com
    http://today.icantfocus.com/blog/