______ Command is used to enable, disable, modify, or drop a constraint in SQL.
2020
______ Command is used to enable, disable, modify, or drop a constraint in SQL.
- A.
MODIFY Table
- B.
DEFINE Table
- C.
ADD Column
- D.
ALTER Table
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Correct answer: D
The ALTER TABLE command is used to change the structure of an existing table. It allows you to add, delete, or modify columns and constraints (like UNIQUE, CHECK, or FOREIGN KEY) without recreating the entire table. The correct option is D.