Message Oracle ORA-36985 - (XSRELGID21) The source relation can be omitted only when using both surrogate GID and level order valueset.

ERROR	(XSRELGID21) The source relation can be omitted only when using both surrogate GID and level order valueset.
CAUSE	Source relation was not specified.
ACTION	Specify the source relation or both surrogate gid and level order valueset.