Thank you for your response.

> From RDB$RELATION_CONSTRAINTS, naturally.

Don't know if it makes a difference, I am using FB 1.5, and I could not find that.

> Have you ever read Language Reference?..

yes, searched the PDF for 'constraint' and that was no help.

I found the following SQL provides the information I need:

SELECT RDB$INDEX_NAME
FROM RDB$INDICES
WHERE RDB$RELATION_NAME='TABLENAME'
AND (RDB$UNIQUE_FLAG IS NOT NULL OR RDB$FOREIGN_KEY IS NOT NULL);

Ed Dressel