WITH CHECK OPTION ANSI: : , , . ,
CREATE VIEW Highratings
AS SELECT cnum, rating
FROM Customers
WHERE rating = 300
WITH CHECK OPTION;
300 . , ( ) :
CREATE VIEW Myratings
AS SELECT *
FROM Highratings;
, 300:
UPDATE Myratings
SET rating = 200
WHERE cnum = 2004;
, , , . WITH CHECK OPTION , , . , , , WITH CHECK OPTION . , , . , , Myratings
CREATE VIEW Myratings
AS SELECT *
FROM Highratings
WITH CHECK OPTION;
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20 21 , . , , . 22 SQL.
SQL
1. ?
#1 CREATE VIEW Dailyorders
AS SELECT DISTINCT cnum, snum, onum, odate
FROM Orders;
#2 CREATE VIEW Custotals
AS SELECT cname, SUM (amt)
FROM Orders, Customers
WHERE Orders.cnum = customer.cnum
GROUP BY cname;
#3 CREATE VIEW Thirdorders
AS SELECT *
FROM Dailyorders
WHERE odate = 10/03/1990;
#4 CREATE VIEW Nullcities
AS SELECT snum, sname, city
FROM Salespeople
WHERE city IS NULL OR sname BETWEEN 'A' AND 'MZ';
2. Commissions (). comm snum. , , .10 .20.
3. SQL , , " CURDATE ". CURDATE , , SQL, , SELECT INSERT. Entryorders . , CURDATE odate, . Entryorders, .
(. A .)
