你可能感興趣的試題

Which of the following is a characteristic of a schema?（）

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.

單項選擇題

Which of the following scenarios will ensure that the value of the NEXT_STEPNO column in a given row of table TABLEX exists as a value of column STEPNO (usually in another row) in the same table?（）

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.