User-defined data types
-----------------------

The Oracle version defines a set of user-defined data types that are
used by functions from the PL/SQL packages. They are not necessary in
PostgreSQL, because of how it deals with arrays and returns of multiple
variables.

-  ``STRARRAY``, a nested table of the data type ``VARCHAR2``

-  ``ID_ARRAY``, a nested table of the data type ``NUMBER``

-  ``DB_VERSION_OBJ``, an object that bundles version information of the
   installed 3D City Database instance

-  ``DB_VERSION_TABLE``, a nested table of ``DB_VERSION_OBJ``

-  ``DB_INFO_OBJ``, an object that bundles metadata of the used reference
   system

-  ``DB_INFO_TABLE``, a nested table of ``DB_INFO_OBJ``

The definition of the data types can be found in the SQL file for the
``CITYDB_UTIL`` package.