单选题Which of the following can be used to ensure that once a row has been inserted in table TABLEX, the column MAINID in that row cannot be updated?()A Define the column MAINID as NOT UPDATABLEB Define the column MAINID as a PRIMARY KEYC Define the column

题目
单选题
Which of the following can be used to ensure that once a row has been inserted in table TABLEX, the column MAINID in that row cannot be updated?()
A

Define the column MAINID as NOT UPDATABLE

B

Define the column MAINID as a PRIMARY KEY

C

Define the column MAINID as a FOREIGN KEY

D

Define an UPDATE trigger on table TABLEX

更多“单选题Which of the following can be used to ensure that once a row has been inserted in table TABLEX, the column MAINID in that row cannot be updated?()A Define the column MAINID as NOT UPDATABLEB Define the column MAINID as a PRIMARY KEYC Define the column ”相关问题