Choose three對象
Which three statements are true about views in an Orade batabase?three
A) A SELECT statement cannot contain a where clause when querying a view contaning a WHERE clause in its defining queryit
B) Rows inserted into a table using a view are retained in the table if the view is doppedtable
C) Views can join tables only if they belong to the same schema.class
D) Views have no segment.object
E) Views have no object number.查詢
F) A view can be created that refers to a non-existent table in its defining query.tab
Answer：BD?di
(解析：view
通過實驗，A 不對;C 不對，視圖能夠和不一樣模式的表進行鏈接查詢;F 不對，若是子查詢中沒有表，建立視圖會報錯;視圖也是對象，因此答案 E 錯誤;