Nice module that enables database handling enhancements for Drupal 7. Since Drupal core might not behave correctly when you correctly use the database, all behaviors will remain discrete and enabled on a per-table definition in the hook_schema().

Current features

Foreign key ON DELETE CASCADE and ON DELETE SET NULL declarations are propagated to the database whenever possible.

Targeted features

SQL column type automatic conversion to PHP types, using converters.
SQL column type conversion based upon definition in hook_schema().

Supported databases

MySQL
PostgreSQL