Store procedure: pre-check for the existence of the foreign key (RegionID) before attempting the insert
1> create table employee(
2> ID int,
3> name nvarchar (10),
4> salary int,
5> start_date datetime,
6> city nvarchar (10),
7> region char (1))
8> GO
1>
2> insert into employee (ID, name, salary, start_date, city, region)
3> values (1, 'Jason', 40420, '02/01/94', 'New York', 'W')
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (2, 'Robert',14420, '01/02/95', 'Vancouver','N')
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (3, 'Celia', 24020, '12/03/96', 'Toronto', 'W')
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (4, 'Linda', 40620, '11/04/97', 'New York', 'N')
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (5, 'David', 80026, '10/05/98', 'Vancouver','W')
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (6, 'James', 70060, '09/06/99', 'Toronto', 'N')
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (7, 'Alison',90620, '08/07/00', 'New York', 'W')
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (8, 'Chris', 26020, '07/08/01', 'Vancouver','N')
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (9, 'Mary', 60020, '06/09/02', 'Toronto', 'W')
3> GO
(1 rows affected)
1>
2> select * from employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
(9 rows affected)
1>
2> --Store procedure: pre-check for the existence of the foreign key (RegionID) before attempting the insert
3>
4> Drop procedure spAdd
5> GO
1>
2> CREATE PROC spAdd @ID nvarchar(20), @City nchar(50), @RegionID nchar(1)
3> AS
4> BEGIN
5> DECLARE @Count INT
6>
7> SELECT @Count = COUNT(*)
8> FROM Employee
9> WHERE Region = @RegionID
10>
11> IF @Count < 1
12> RAISERROR ('RegionID is not valid. Please check your RegionID and try again.', 11, 1)
13> ELSE
14> INSERT INTO Employee (ID, City, Region)
15> VALUES (@ID, @City, @RegionID)
16> END
17> GO
1>
2> EXEC spAdd @ID=99, @City = 'DDD', @RegionID='N'
3> GO
(1 rows affected)
1>
2> select * from employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
99 NULL NULL NULL DDD N
(10 rows affected)
1>
2> EXEC spAdd @ID=99, @City = 'DDD', @RegionID='A'
3> GO
Msg 50000, Level 11, State 1, Server JAVA2S\SQLEXPRESS, Procedure spAdd, Line 12
RegionID is not valid. Please check your RegionID and try again.
1>
2> select * from employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
99 NULL NULL NULL DDD N
(10 rows affected)
1>
2> drop table employee
3> GO
1>