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Choose three
Which three statements are true about views in an Orade batabase?
A) A SELECT statement cannot contain a where clause when querying a view contaning a WHERE clause in its defining query
B) Rows inserted into a table using a view are retained in the table if the view is dopped
C) Views can join tables only if they belong to the same schema.
D) Views have no segment.
E) Views have no object number.
F) A view can be created that refers to a non-existent table in its defining query.
Answer：BD?
(解析：
經(jīng)過實驗，A 不對;C 不對，視圖可以和不同模式的表進(jìn)行連接查詢;F 不對，如果子查詢中沒有表，創(chuàng)建視圖會報錯;視圖也是對象，所以答案 E 錯誤;
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