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DBIx::Class::InflateColumn
Automatically create references from column data

DBIx::Class::InflateColumn - Automatically create references from column data


NAME

DBIx::Class::InflateColumn - Automatically create references from column data


SYNOPSIS


    # In your table classes

    __PACKAGE__->inflate_column('column_name', {

        inflate => sub { ... },

        deflate => sub { ... },

    });


DESCRIPTION

This component translates column data into references, i.e. ``inflating'' the column data. It also ``deflates'' references into an appropriate format for the database.

It can be used, for example, to automatically convert to and from DateTime objects for your date and time fields. There's a conveniece component to actually do that though, try the DBIx::Class::InflateColumn::DateTime manpage.

It will handle all types of references except scalar references. It will not handle scalar values, these are ignored and thus passed through to the SQL::Abstract manpage. This is to allow setting raw values to ``just work''. Scalar references are passed through to the database to deal with, to allow such settings as \'year + 1' and \'DEFAULT' to work.

If you want to filter plain scalar values and replace them with something else, contribute a filtering component.


METHODS

inflate_column

Instruct the DBIx::Class manpage to inflate the given column.

In addition to the column name, you must provide inflate and deflate methods. The inflate method is called when you access the field, while the deflate method is called when the field needs to used by the database.

For example, if you have a table events with a timestamp field named insert_time, you could inflate the column in the corresponding table class using something like:


    __PACKAGE__->inflate_column('insert_time', {

        inflate => sub { DateTime::Format::Pg->parse_datetime(shift); },

        deflate => sub { DateTime::Format::Pg->format_datetime(shift); },

    });

(Replace the DateTime::Format::Pg manpage with the appropriate module for your database, or consider the DateTime::Format::DBI manpage.)

The coderefs you set for inflate and deflate are called with two parameters, the first is the value of the column to be inflated/deflated, the second is the row object itself. Thus you can call ->result_source->schema->storage->dbh in your inflate/defalte subs, to feed to the DateTime::Format::DBI manpage.

In this example, calls to an event's insert_time accessor return a DateTime object. This DateTime object is later ``deflated'' when used in the database layer.

get_inflated_column


  my $val = $obj->get_inflated_column($col);

Fetch a column value in its inflated state. This is directly analogous to get_column in the DBIx::Class::Row manpage in that it only fetches a column already retreived from the database, and then inflates it. Throws an exception if the column requested is not an inflated column.

set_inflated_column


  my $copy = $obj->set_inflated_column($col => $val);

Sets a column value from an inflated value. This is directly analogous to set_column in the DBIx::Class::Row manpage.

store_inflated_column


  my $copy = $obj->store_inflated_column($col => $val);

Sets a column value from an inflated value without marking the column as dirty. This is directly analogous to store_column in the DBIx::Class::Row manpage.


SEE ALSO

the DBIx::Class::Core manpage - This component is loaded as part of the ``core'' the DBIx::Class manpage components; generally there is no need to load it directly


AUTHOR

Matt S. Trout <mst@shadowcatsystems.co.uk>


CONTRIBUTORS

Daniel Westermann-Clark <danieltwc@cpan.org> (documentation)

Jess Robinson <cpan@desert-island.demon.co.uk>


LICENSE

You may distribute this code under the same terms as Perl itself.

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