DISTINCT data types

IBM^® Informix^® supports DISTINCT data types as User Defined Types based on a source data type, but with different casts and functions than those on the source data type.

Genero BDL partially supports the IBM Informix DISTINCT data types:

The fgldbsch schema extractor can extract columns defined with a distinct type and write the distinct type code in the .sch schema file. For more details, see the list of distinct types in the Column Definition File (.sch)

However, there are some restrictions you must be aware of:

• It is not possible to define BDL variables explicitly with the name of a distinct type. Variables must be defined indirectly with the schema by using the DEFINE LIKE statement.
• The static SQL syntax does not support OPAQUE-related syntax elements:
  • The DDL statements CREATE DISTINCT TYPE, DROP TYPE, CREATE CAST, and DROP CAST are not allowed,
  • In CREATE TABLE / ALTER TABLE DDL statements, the data type must be a built-in type.
  • The :: cast operator is not supported.

Enhancement reference: 20003