This document discusses stored procedures in SQL. It explains that stored procedures allow SQL commands to be stored in a database and have more capabilities than scripts. It covers how to create and execute stored procedures, including using parameters, variables, and control flow statements. Stored procedures allow passing data into and out of the procedure and returning values.

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