Invalid reference to or operation on constraint '%1'

Error constant SQLE_INVALID_CONSTRAINT_REF
ODBC 2 State S0002
ODBC 3 State 42S23
Parameter 1 Name of the constraint can not be used for the specified purpose.
Severity 16
SQLCODE –937
SQLSTATE 42U06
Sybase error code 13550
Probable cause

You specified an invalid operation on a constraint. For example, you tried to alter a primary key constraint.