This is a simple plugin to a Class::DBI subclass that allows for simple
sorting of the results of a retrieve_all().
There are two main ways to use this.
Firstly, we create a new method retrieve_all_sorted_by which takes an
argument of how to sort.
We also add a method for retrieve_all_sort_field that sets a default
field that any retrieve_all() will use for sorting.
my @by_date = My::Class->retrieve_all_sorted_by("date");
This method will be exported into the calling class, and allows for
retrieving all the objects of the class, sorted by the given column.
The argument given will be passed straight through to the database as
is, and is not checked in any way, so an error here will usually
in an error from the database, rather than Class::DBI itself.
This makes it possible to pass more complex ORDER BY clauses through:
my @by_date = My::Class->retrieve_all_sorted_by("date DESC, reference_no");