Whichtwostatementsaretrueabouttheprimarykeyconstraintinatable?()

A.Itisnotpossibletodisabletheprimarykeyconstraint. B.Itispossibletohavemorethanoneprimarykeyconstraintinasingletable. C.Theprimarykeyconstraintcanbereferredbyonlyoneforeignkeyconstraint. D.Theprimarykeyconstraintcanbeimposedbycombiningmorethanonecolumn. E.Thenon-deferrableprimarykeyconstraintcreatesanuniqueindexontheprimarykeycolumnifitisnotalreadyindexed.

时间:2023-09-10 17:20:27

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