DBIx::Class::InflateColumn(3) Automatically create references from column data

SYNOPSIS


# In your table classes
__PACKAGE__->inflate_column('column_name', {
inflate => sub {
my ($raw_value_from_db, $result_object) = @_;
...
},
deflate => sub {
my ($inflated_value_from_user, $result_object) = @_;
...
},
});

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 convenience component to actually do that though, try DBIx::Class::InflateColumn::DateTime.

It will handle all types of references except scalar references. It will not handle scalar values, these are ignored and thus passed through to SQL::Abstract. 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, see DBIx::Class::FilterColumn.

METHODS

inflate_column

Instruct DBIx::Class 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 {
          my ($insert_time_raw_value, $event_result_object) = @_;
          DateTime->from_epoch( epoch => $insert_time_raw_value );
        },
        deflate => sub {
          my ($insert_time_dt_object, $event_result_object) = @_;
          $insert_time_dt_object->epoch;
        },
    });

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 result object itself.

In this example, calls to an event's "insert_time" accessor return a DateTime object. This DateTime object is later ``deflated'' back to the integer epoch representation when used in the database layer. For a much more thorough handling of the above example, please see DBIx::Class::DateTime::Epoch

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 DBIx::Class::Row in that it only fetches a column already retrieved 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 DBIx::Class::Row.

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 DBIx::Class::Row.

FURTHER QUESTIONS?

Check the list of additional DBIC resources.

COPYRIGHT AND LICENSE

This module is free software copyright by the DBIx::Class (DBIC) authors. You can redistribute it and/or modify it under the same terms as the DBIx::Class library.

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