CREATE TRIGGER FOR DELETE : Trigger for Delete « Trigger « SQL Server / T-SQL Tutorial






2>
3> CREATE TABLE Customers (
4>      CustomerID nchar (5) NOT NULL ,
5>      CompanyName nvarchar (40) NOT NULL ,
6>      ContactName nvarchar (30) NULL ,
7>      ContactTitle nvarchar (30) NULL ,
8>      Address nvarchar (60) NULL ,
9>      City nvarchar (15) NULL ,
10>     Region nvarchar (15) NULL ,
11>     PostalCode nvarchar (10) NULL ,
12>     Country nvarchar (15) NULL ,
13>     Phone nvarchar (24) NULL ,
14>     Fax nvarchar (24) NULL
15> )
16> GO
1>
2> INSERT Customers VALUES('1','A','Maria',    'Sales',  'Str. 57', 'Berlin'    ,NULL,'12209', 'Germany','111-1111111','111-1111111')
3> INSERT Customers VALUES('2','M','Joe',      'Owner',  'Ave. 231','Vancouver' ,NULL,'05023', 'Mexico', '(222) 222-3332',NULL)
4> INSERT Customers VALUES('3','H','Thomas',   'Sales',  'Sq.  111','London'    ,NULL,'1D00P', 'UK',     '(444) 444-4444','(444) 444-4444')
5> INSERT Customers VALUES('4','B','Berg',     'Order',  'Blv    8','Toronto'   ,NULL,'00222', 'Sweden', '4444-55 55 65','5555-55 55 55')
6> INSERT Customers VALUES('5','S','Moos',     'Sales',  'Fort  57','New York'  ,NULL,'68306', 'Germany','6666-66666','6666-77777')
7> INSERT Customers VALUES('6','F','Cite',     'Manager','24      ','Dalles'    ,NULL,'67000', 'France', '88.60.15.31','88.60.15.32')
8> INSERT Customers VALUES('7','C','Sommer',   'Owner',  'Araq, 67','Paris'     ,NULL,'28023', 'Spain',  '(91) 555 22 82','(91) 555 91 99')
9> INSERT Customers VALUES('8','P','Leb',      'Owner',  '12      ','Beijing'   ,NULL,'13008', 'France', '91.24.45.40','91.24.45.41')
10> INSERT Customers VALUES('9','D','Elizabeth','Manager','23 Blvd.','Tsawassen','BC', 'T2F8M4','Canada', '(604) 555-4729','(604) 555-3745')
11> go

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)

(1 rows affected)
1>
2> CREATE TABLE Orders (
3>      OrderID int IDENTITY (1, 1) NOT NULL ,
4>      CustomerID nchar (5) NULL ,
5>      EmployeeID int NULL ,
6>      OrderDate datetime NULL ,
7>      RequiredDate datetime NULL ,
8>      ShippedDate datetime NULL ,
9>      ShipVia int NULL ,
10>     Freight money NULL DEFAULT (0),
11>     ShipName nvarchar (40) NULL ,
12>     ShipAddress nvarchar (60) NULL ,
13>     ShipCity nvarchar (15) NULL ,
14>     ShipRegion nvarchar (15) NULL ,
15>     ShipPostalCode nvarchar (10) NULL ,
16>     ShipCountry nvarchar (15) NULL
17> )
18> GO
1>
2>    CREATE TRIGGER CustomerHasOrders
3>       ON Customers
4>       FOR DELETE
5>    AS
6>       IF EXISTS
7>          (
8>           SELECT 'True'
9>           FROM Deleted d
10>           JOIN Orders o
11>              ON d.CustomerID = o.CustomerID
12>          )
13>
14>          BEGIN
15>             RAISERROR('Customer has Order History. Delete failed!', 16,1)
16>             ROLLBACK TRAN
17>          END
18> GO
1>    DELETE Customers
2>       WHERE CustomerID = 'WHITC'
3> GO

(0 rows affected)
1>
2>
3> drop TRIGGER CustomerHasOrders;
4> GO
1>
2> drop table Customers;
3> GO
1> drop table orders;
2> GO








22.4.Trigger for Delete
22.4.1.CREATE TRIGGER FOR DELETE
22.4.2.Trigger for delete and deleted table
22.4.3.After its data has been deleted, the trigger deletes corresponding rows from the sales and discounts tables.
22.4.4.CREATE TRIGGER FOR INSERT, UPDATE, DELETE