单选题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?（）ADefine a UNIQUE constraint on the columns NEXT_STEPNO and STEPNO.BDefine a CHECK constraint on the NEXT_STEPNO column (NEXT_STEPNO = STEPNO).CDefine column STEPNO as the primary key of TABLEX and column NEXT_STEPNO as a foreign key referencing column STEPNO of the same table.DDefine column NEXT_STEPNO as the primary key of TABLEX and column STEPNO as a foreign key referencing column NEXT_STEPNO in the same table.
单选题
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.
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