Informix Error -9640: Cannot drop type (type_name): distinct type defined over the type.

Reasons / Common Causes

-9640 fires when DROP TYPE targets a type that a distinct type is still defined over — per the official guidance.

1. A distinct type still based on the target type, per the official guidance — the direct, only cause.

Solutions / Resolution

1. Drop all distinct types based on the type first, per the official guidance, before dropping the type itself.

Examples

Dropping a type with a dependent distinct type

CREATE DISTINCT TYPE di AS my_opaque_type;
DROP TYPE my_opaque_type RESTRICT;   -- -9640: di still depends on it

Corrected

DROP TYPE di RESTRICT;
DROP TYPE my_opaque_type RESTRICT;

Diagnostic Checks

1. Check the system catalog for distinct types based on the target type, and drop them first.

Related Errors / Related Topics

• -9630 — "Cannot drop type (type_name): still in use." The general in-use error this is a specific case of, naming a distinct type as the specific dependent.

The type is still in use as the base of a distinct type — drop the distinct type first.