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：

经过实验，A 不对;C 不对，视图可以和不同模式的表进行连接查询;F 不对，如果子查询中没有表，创建视图会报错;视图也是对象，所以答案 E 错误;