"cannot modify %s.%s more than once in a transaction"
*Cause: An attempt was made to modify an object more than once in a
transaction. This error is usually caused by a DDL statement that
fires a system trigger that tries to modify the same object.
It can also happen when an attempt is made to perform more than
one DDL operation on a queue table in the same transaction
without issuing a commit between operations.
*Action: Do not create system triggers that might modify an already
modified object. Also, do not specify more than one DDL
operation on a queue table in the same transaction.