++ed by:
ABRAXXA

1 PAUSE user

Bernhard Graf

NAME

DBIx::Class::InflateColumn::Boolean - Auto-create boolean objects from columns.

VERSION

Version 0.003000

SYNOPSIS

Load this component and declare columns as boolean values.

  package Table;
  __PACKAGE__->load_components(qw/InflateColumn::Boolean Core/);
  __PACKAGE__->table('table');
  __PACKAGE__->true_is('Y');
  __PACKAGE__->add_columns(
      foo => {
          data_type => 'varchar',
          is_boolean  => 1,
      },
      bar => {
          data_type => 'varchar',
          is_boolean  => 1,
          true_is     => qr/^(?:yes|ja|oui|si)$/i,
      },
      baz => {
          data_type => 'int',
          is_boolean  => 1,
          false_is    => ['0', '-1'],
      },
  );

Then you can treat the specified column as a boolean:

  print 'table.foo is ', $table->foo ? 'true' : 'false', "\n";
  print 'table.bar is ', $table->bar ? 'true' : 'false', "\n";

The boolean object still stringifies to the actual field value:

  print $table->foo;  # prints "Y" if it is true

DESCRIPTION

Perl does not have a native boolean data type by itself, it takes certain several scalar values as false (like '', 0, 0.0) as well as empty lists and undef, and everything else is true. It is also possible to set the boolean value of an object instance.

As in most program code you have boolean data in nearly every database. But for a database it is up to the designer to decide what is true and what is false.

This module maps such "database booleans" into "Perl booleans" and back by inflating designated columns into objects that store the original value, but also evaluate as true or false in boolean context. Therefore - if "Yes" in the database means true and "No" means false in the application the following two lines can virtually mean the same:

  if ($table->field eq "No") { ... }
  if (not $table->field) { ... }

That means that $table->field has the scalar value "No", but is taken as false in a boolean context, whereas Perl would normally regard the string "No" as true.

When writing to the database, of course $table->field would be deflated to the original value "No" and not some Perlish form of a boolean.

Important Notice

It is strongly encouraged to assign normal database values to a boolean field when creating a fresh row, because:

KISS (http://en.wikipedia.org/wiki/KISS_principle)

Just say "No" when you mean it.

Don't rely on the current boolean class

Take the underlying boolean class as a black box. It might be replaced by something other in future versions of this module.

Simply assign the appropriate scalars to boolean fields ("Yes" or "No" for the above example).

Another Important Notice

A database NULL value is mapped to Perl's undef and is never inflated. Therefore NULL is false and this can not be altered.

METHODS

true_is

  __PACKAGE__->true_is('Y');
  __PACKAGE__->true_is(['Y', 'y']);
  __PACKAGE__->true_is(qr/^(y|yes|true|1)$/i);

Gets/sets the possible values for true data in this table. Can be either a scalar, a reference to an array of scalars or a regular expression (qr/.../).

The last line in the above example shows this package's default for what is true when neither true_is nor "false_is" are set.

false_is

  __PACKAGE__->false_is('N');
  __PACKAGE__->false_is(['N', 'n']);
  __PACKAGE__->false_is(qr/^(n|no|false|0)$/i);

Gets/sets the possible values for false data in this table. Can be either a scalar, a reference to an array of scalars or a regular expression (qr/.../).

register_column

Chains with "register_column" in DBIx::Class::Row, and sets up boolean columns appropriately. This would not normally be called directly by end users.

SEE ALSO

DBIx::Class, DBIx::Class::InflateColumn

AUTHOR

Bernhard Graf

BUGS

Please report any bugs or feature requests through the web interface at https://github.com/augensalat/DBIx-Class-InflateColumn-Boolean/issues. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

COPYRIGHT & LICENSE

Copyright 2008-2016 Bernhard Graf, all rights reserved.

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