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
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参考答案和解析
正确答案：
C
解析：
暂无解析