42.Which three statements are true regarding views? (Choose three.)

42.Which three statements are true regarding views? (Choose three.)

A.Views can be created only from tables.

B.Views can be created from tables or other views.

C.Only simple views can use indexes existing on the underlying tables.

D.Both simple and complex views can use indexes existing on the underlying tables.

E.Complex views can be created only on multiple tables that exist in the same schema.

F.Complex views can be created on multiple tables that exist in the same or different schemas.

答案：BDF

A：错误，可以从视图创建

B：正确

C：错误，复杂视图也可以

D：正确

E：错误，不同schema下的表，也可以创建，只要能访问就行

F：正确