ORCALE VIEWS

1.CREATE ORACLE VIEW

   CREATE OR REPLACE VIEW myview
    AS
    SELECT * FROM books WHERE price>30
    WITH CHECK OPTION  --When INSERT DATA THROUGH VIEW,If the DATA IS NOT

                                    -- IN THE WHERE ,IT CAN'T BE INSERT INTO
    /

2.CREATE READ ONLY VIEW

 CREATE OR REPLACE VIEW v_read
 AS
 SELECT eid,ename FROM emp
 WITH READ ONLY  --CAN'T INSERT INTO DATA

/

--WHEN THE VIEW IS NOT ONLY IN ONE TABLE OR HAVE GROUP BY, DISTINCT AND SO ON, CAN'T INSERT INTO DATA TOO.OFTEN,VIEW IS USED FOR SELECT ONLY.

4.DISPLAY VIEW

SELECT TEXT FROM User_views WHERE VIEW_NAME ='V_READ'
/
 DESC USER_views(dba_views)--DISPLAY ALL USER VIEWS