Mega Code Archive
Rollback transaction in a trigger
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5>
6> CREATE TABLE Products (
7> ProductID int NOT NULL ,
8> ProductName nvarchar (40) NOT NULL ,
9> SupplierID int NULL ,
10> CategoryID int NULL ,
11> QuantityPerUnit nvarchar (20) NULL ,
12> UnitPrice money NULL,
13> UnitsInStock smallint NULL,
14> UnitsOnOrder smallint NULL,
15> ReorderLevel smallint NULL,
16> Discontinued bit NOT NULL
17> )
18> GO
1> INSERT Products VALUES(1,'F',15,4,'10 - 999 g pkgs.',61.5,66,6,6,6)
2> INSERT Products VALUES(2,'M',14,4,'24 - 888 g pkgs.',34.8,74,7,7,7)
3> INSERT Products VALUES(3,'R',17,8,'24 - 777 g jars',17,171,0,5,0)
4> INSERT Products VALUES(4,'L',4,7,'5 kg pkg.',10,4,20,5,0)
5> INSERT Products VALUES(5,'R',12,1,'24 - 0.5 l bottles',1.23,445,0,25,0)
6> INSERT Products VALUES(6,'L',23,1,'500 ml',18,57,1,20,0)
7> INSERT Products VALUES(7,'O',12,2,'12 boxes',13,23,0,15,0)
8> go
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
(1 rows affected)
1>
2> create TRIGGER ProductIsRationed
3> ON Products
4> FOR UPDATE
5> AS
6> IF UPDATE(UnitsInStock)
7> BEGIN
8> IF EXISTS
9> (
10> SELECT 'True'
11> FROM Inserted i
12> JOIN Deleted d
13> ON i.ProductID = d.ProductID
14> WHERE (d.UnitsInStock - i.UnitsInStock) > d.UnitsInStock / 2
15> AND d.UnitsInStock - i.UnitsInStock > 0
16> )
17> BEGIN
18> RAISERROR('Cannot reduce stock by more than 50%% at once.',16,1)
19> ROLLBACK TRAN
20> END
21> END
22> GO
1>
2> drop TRIGGER ProductIsRationed;
3> GO
1>
2> drop table Products;
3> GO
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