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單項選擇題

Which of the following supports the XML data type?（）

A.A unique index
B.A composite index
C.A check constraint
D.A generated column

單項選擇題

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