GNATCOLL.SQL easier to add new field types
It is now easier to add new field types. GNATCOLL used to have enumeration types internally, which meant that adding new types had mostly to be done by modifying GNATCOLL itself. See the package GNATCOLL.SQL_Fields for an example. The JSON and XML field types now use this new framework, as an example. This means that if you are using these in applications currently, you will likely need to add a 'with GNATCOLL.SQL_Fields;' to keep your code compiling.