Foreign key '%1' for table '%2' duplicates an existing foreign key

Item Value
SQLCODE -251
Constant SQLE_DUPLICATE_FOREIGN_KEY
SQLSTATE 52W06
Sybase error code 1909
ODBC 2 State 42000
ODBC 3 State 42000
Parameter 1 The role name of the new foreign key.
Parameter 2 The table containing the foreign key.

Probable cause 

You attempted to define a foreign key that already exists.