Which of the following database objects can be used to raise an error if a table is updated?（）

A.Foreign key references cannot cross schema boundaries.
B.A DB2 user must be created before a schema with the same name can be created.
C.If no schema is specified when an object is created, the default schema PUBLIC is used.
D.A schema enables the creation of multiple objects in a database without encountering namespace collisions.

A.Define a UNIQUE constraint on the columns NEXT_STEPNO and STEPNO.
B.Define a CHECK constraint on the NEXT_STEPNO column (NEXT_STEPNO = STEPNO).
C.Define column STEPNO as the primary key of TABLEX and column NEXT_STEPNO as a foreign key referencing column STEPNO of the same table.
D.Define column NEXT_STEPNO as the primary key of TABLEX and column STEPNO as a foreign key referencing column NEXT_STEPNO in the same table.

A.GRAPHIC
B.BINARY
C.IMAGE
D.BLOB