单选题Which syntax turns an existing constraint on?（）AALTER TABLE table_name ENABLE constraint_name;BALTER TABLE table_name STATUS = ENABLE CONSTRAINT constraint_name;CALTER TABLE table_name ENABLE CONSTRAINT constraint_name;DALTER TABLE table_name STATUS ENABLE CONSTRAINT constraint_name;EALTER TABLE table_name TURN ON CONSTRAINT constraint_name;
单选题
Which syntax turns an existing constraint on?（）
A
ALTER TABLE table_name ENABLE constraint_name;
B
ALTER TABLE table_name STATUS = ENABLE CONSTRAINT constraint_name;
C
ALTER TABLE table_name ENABLE CONSTRAINT constraint_name;
D
ALTER TABLE table_name STATUS ENABLE CONSTRAINT constraint_name;
E
ALTER TABLE table_name TURN ON CONSTRAINT constraint_name;
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