Index '%1' for table '%2' would not be unique

Error constant SQLE_INDEX_NOT_UNIQUE
ODBC 2 state 23000
ODBC 3 state 23000
Parameter 1 Name of the index that would not be unique.
Parameter 2 Name of the table that contains the index.
Severity 16
SQLCODE -196
SQLSTATE 23505
Sybase error code 548
 Probable cause