Torsten Raudssus > DBIx-Class > DBIx::Class::FilterColumn

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NAME ^

DBIx::Class::FilterColumn - Automatically convert column data

SYNOPSIS ^

In your Schema or DB class add "FilterColumn" to the top of the component list.

  __PACKAGE__->load_components(qw( FilterColumn ... ));

Set up filters for the columns you want to convert.

 __PACKAGE__->filter_column( money => {
     filter_to_storage => 'to_pennies',
     filter_from_storage => 'from_pennies',
 });

 sub to_pennies   { $_[1] * 100 }

 sub from_pennies { $_[1] / 100 }

 1;

DESCRIPTION ^

This component is meant to be a more powerful, but less DWIM-y, DBIx::Class::InflateColumn. One of the major issues with said component is that it only works with references. Generally speaking anything that can be done with DBIx::Class::InflateColumn can be done with this component.

METHODS ^

filter_column

 __PACKAGE__->filter_column( colname => {
     filter_from_storage => 'method'|\&coderef,
     filter_to_storage   => 'method'|\&coderef,
 })

This is the method that you need to call to set up a filtered column. It takes exactly two arguments; the first being the column name the second being a hash reference with filter_from_storage and filter_to_storage set to either a method name or a code reference. In either case the filter is invoked as:

  $row_obj->$filter_specification ($value_to_filter)

with $filter_specification being chosen depending on whether the $value_to_filter is being retrieved from or written to permanent storage.

If a specific directional filter is not specified, the original value will be passed to/from storage unfiltered.

get_filtered_column

 $obj->get_filtered_column('colname')

Returns the filtered value of the column

set_filtered_column

 $obj->set_filtered_column(colname => 'new_value')

Sets the filtered value of the column

EXAMPLE OF USE ^

Some databases have restrictions on values that can be passed to boolean columns, and problems can be caused by passing value that perl considers to be false (such as undef).

One solution to this is to ensure that the boolean values are set to something that the database can handle - such as numeric zero and one, using code like this:-

    __PACKAGE__->filter_column(
        my_boolean_column => {
            filter_to_storage   => sub { $_[1] ? 1 : 0 },
        }
    );

In this case the filter_from_storage is not required, as just passing the database value through to perl does the right thing.

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