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Question 43

Which three statements are true about views in an Oracle Database? (Choose three.)

A SELECT statement cannot contain a WHERE clause when querying a view containing a WHERE clause in its defining query.

Views have no segment.

Views have no object number.

Views can join tables only if they belong to the same schema.

A view can be created that refers to a non-existent table in its defining query.

Rows inserted into a table using a view are retained in the table if the view is dropped.

Correct Answer: B, E, F

Views in an Oracle Database have no segment as they do not occupy physical storage; they are simply stored queries. A view can be created that refers to a non-existent table using the FORCE option in the CREATE VIEW statement; this means the view will be created but will throw an error when queried. Rows inserted into a table using a view are retained in the table even if the view is subsequently dropped, as views are just a way to look at the data and not a data storage mechanism themselves.

Discussion

KizTine

I don't understand the answer E. How can views refers to non-existent table ?

lucemqy

You can create view to non-existent table or table with invalid columns by using FORCE option in the CREATE VIEW command. When you query the data from the view you will get an error

cadcadley

what that is mean no segment about view

ArslanAltaf

segment mean physical storage ...

TheOracleWasTakenOptions: BEF

select object_id, object_name from user_objects In this table you will also find views so they do have an object number. Views have no segment since they don't take up physical space