Which command(s) is(are) used to enable/disable/drop an integrity constraint in SQL?

A. update files B. print files on paper C. data entry D. All of the above E. None of the above

A. tree B. relational C. network D. chain E. All of the above

A. database design B. backing up the database C. performance monitoring D. user coordination E. All of the above

A. Print B. Sort C. Look-up D. All of the above E. None of the above