1. Stored Procedures
CIS-182

2. BATCH
• Batch is a logical group of SQL statements
– Run-time error will halt execution only of FURTHER
steps
– Can break up work
• Stored procedures
• User-defined functions
• Views

3. Scripts v. Stored Procedures
• Script: Text file of SQL commands
• Stored Procedure: SQL commands stored in
database itself
– SPROC’s have more capabilities than a script

4. Format of SPROC’s
CREATE PROC <name>
<parameter list>
AS
<instructions to execute>

5. EXECUTE
• EXEC(cute) statement
OR
• EXEC(cute) stored procedure name
• Statement or sproc runs in it’s own scope
– Can’t ‘share’ variables directly
– User’s security rules apply
– Can’t be used in User Defined Function (UDF)

6. Uses of Stored Procedures
• For returning data
• For editing data
• For calculations

7. Parameters
• Method for sending data into and from a stored
procedure
– INPUT parameters are values sent in
– OUTPUT parameters are values returned
• Must have a holding space (variable) for the returned data
• Defined before start of procedure (AS)

8. Declaring Parameters
• Include name and datatype
• Default value is optional
– Without a default value, parameter is required
• Direction is optional (input is default)
– An output parameter must have direction specified

9. Sample Input Parameter
CREATE PROC upFindStudent
@SID char(9)
AS
SELECT *
FROM Students_T
Where SchoolID=@SID

10. Sample Output Parameter
CREATE PROC upFindStudentID
@First varchar(25),
@Last varchar(35),
@SID char(9) OUTPUT
AS
SELECT @SID=SchoolID
FROM Students_T
Where @First=Firstname and
@Last=Lastname

11. Variables
• Create using DECLARE
• Need to start with ‘@’
• Can use SQL data types or custom data types
DECLARE @StudentName varchar(50)

12. Variable Assignment
• SET is usually used similar to procedural
language
SET @Var=value
• SELECT is usually used when getting a value
from a query
SELECT @Var=Sum(PossiblePoints) FROM
Assignments

13. Return Values
• Result of stored procedure indicates success or
failure
• Non-zero value indicates a problem
• Must be an integer
• Different from an output parameter
– Output parameter is about data
• RETURN <value>
– Causes immediate exit

14. Decision-making
• IF … ELSE
– No end if
– Need to use Begin/End if have more than one
instruction to execute
IF StartDate < EndDate
Begin
…
End
ELSE

15. Simple Case Statement
• CASE
– Similar to SELECT CASE or SWITCH
– Compares one value to different cases
CASE Category
WHEN ‘pop_comp’ THEN ‘Popular Computing’
WHEN ‘mod_cook’ THEN ‘Modern Cooking’
END

16. Searched CASE
• No test expression
• Each WHEN has a boolean test
CASE
WHEN Points >= 90 THEN ‘A’
WHEN Points < 90 AND Extra > 0
THEN ‘A’
END

17. @@Error –
System Variable
• Determined after each SQL statement;
• 0 means statement was successful
• Number other than zero is typically a specific
error
• Can store value in variable and test

18. @@Identity –
System Variable
• Returns the last identity value used as a result of
INSERT or SELECT INTO
• Returns Null if operation failed or a value
wasn’t generated
• Returns last number created if multiple inserts
occur (i.e. SELECT INTO)

19. @@Rowcount –
System Variables
• Number of rows returned or affected by the last
statement
• 0 (zero) is often used as a logical test
– If no records found for where clause, notify system or
process