SQL Server/T-SQL Tutorial/Trigger/Trigger on view

CREATE INSTEAD OF DELETE TRIGGER ON a view

1>
2> SET NOCOUNT ON
3>
4> CREATE TABLE Table1
5> (a int  PRIMARY KEY,
6>  b datetime default getdate(),
7>  c varchar(10))
8>
9>
10> CREATE TABLE Table2
11>  (a int
12>   ,message varchar(100))
13> GO
1>
2> INSERT INTO Table1(a) VALUES (1)
3> INSERT INTO Table1(a) VALUES (2)
4> INSERT INTO Table1(a) VALUES (3)
5> INSERT INTO Table1(a) VALUES (4)
6>
7> INSERT INTO Table2 VALUES (1, "first row")
8> INSERT INTO Table2 VALUES (1, "second row")
9> INSERT INTO Table2 VALUES (2, "first row")
10> INSERT INTO Table2 VALUES (2, "second row")
11> INSERT INTO Table2 VALUES (2, "third row")
12> INSERT INTO Table2 VALUES (3, "first row")
13> GO
Msg 2627, Level 14, State 1, Server J\SQLEXPRESS, Line 2
Violation of PRIMARY KEY constraint "PK__Table1__686944BF". Cannot insert duplicate key in object "dbo.Table1".
The statement has been terminated.
Msg 2627, Level 14, State 1, Server J\SQLEXPRESS, Line 3
Violation of PRIMARY KEY constraint "PK__Table1__686944BF". Cannot insert duplicate key in object "dbo.Table1".
The statement has been terminated.
Msg 2627, Level 14, State 1, Server J\SQLEXPRESS, Line 4
Violation of PRIMARY KEY constraint "PK__Table1__686944BF". Cannot insert duplicate key in object "dbo.Table1".
The statement has been terminated.
Msg 2627, Level 14, State 1, Server J\SQLEXPRESS, Line 5
Violation of PRIMARY KEY constraint "PK__Table1__686944BF". Cannot insert duplicate key in object "dbo.Table1".
The statement has been terminated.
1>
2> CREATE VIEW join_view AS
3> SELECT Table1.a as a1, b, c,
4>        Table2.a as a2, message
5> FROM Table1 join Table2
6> ON Table1.a = Table2.a
7> GO
1>
2> CREATE TRIGGER DEL_JOIN
3> ON join_view
4> INSTEAD OF DELETE
5>
6> AS
7>   DELETE Table1
8>     WHERE a IN (SELECT a1 FROM deleted)
9>   DELETE Table2
10>     WHERE a IN (SELECT a2 FROM deleted)
11> GO
1>
2> drop TRIGGER DEL_JOIN;
3> drop VIEW join_view;
4>

INSTEAD OF INSERT on a view

6> CREATE TABLE orders
7>         (orderid INT NOT NULL,
8>         price MONEY NOT NULL,
9>         quantity INT NOT NULL,
10>         orderdate DATETIME NOT NULL,
11>         total AS price * quantity,
12>         shippeddate AS DATEADD (DAY, 7, orderdate))
13> GO
1>
2> CREATE VIEW all_orders
3>         AS SELECT orderid, price, quantity, orderdate, total, shippeddate
4>         FROM orders
5> GO
1>
2> CREATE TRIGGER tr_orders ON all_orders INSTEAD OF INSERT
3> AS BEGIN
4>    INSERT INTO orders SELECT orderid, price, quantity, orderdate FROM inserted
5> END
6> GO
1>
2> drop trigger tr_orders;
3> GO
1>
2> drop view all_orders;
3> GO
1>
2> drop table orders;

INSTEAD OF UPDATE trigger on a view

2>
3>
4> CREATE TABLE Customers (
5>      CustomerID nchar (5) NOT NULL ,
6>      CompanyName nvarchar (40) NOT NULL ,
7>      ContactName nvarchar (30) NULL ,
8>      ContactTitle nvarchar (30) NULL ,
9>      Address nvarchar (60) NULL ,
10>     City nvarchar (15) NULL ,
11>     Region nvarchar (15) NULL ,
12>     PostalCode nvarchar (10) NULL ,
13>     Country nvarchar (15) NULL ,
14>     Phone nvarchar (24) NULL ,
15>     Fax nvarchar (24) NULL
16> )
17> 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 VIEW CustomerOrders_vw
3>    WITH SCHEMABINDING
4>    AS
5>    SELECT   cu.rupanyName
6>    FROM     dbo.Customers  AS cu
7>    GO
1>
2>
3>
4>
5>    create TRIGGER trCustomerOrderUpdate ON CustomerOrders_vw
6>    INSTEAD OF UPDATE
7>    AS
8>    BEGIN
9>        IF (SELECT COUNT(*) FROM Inserted) > 0
10>        BEGIN
11>            IF (COLUMNS_UPDATED() | 96) != 96
12>            BEGIN
13>                RAISERROR("Updates only supported for UnitPrice and Quantity", 16,1)
14>            END
15>            ELSE BEGIN
16>                RAISERROR("again", 16,1)
17>
18>            END
19>        END
20>    END
21> GO
1> drop TRIGGER trCustomerOrderUpdate;
2> drop view CustomerOrders_vw;
3> drop table Customers;
4> GO