Dexterity | CONFIDENTIAL 2009 MRO | Analytics | Insights 1 Stored Procedures.

Dexterity | CONFIDENTIAL 2009 MRO | Analytics | Insights 1

Stored Procedures


Stored Procedure

A stored procedure is a precompiled object stored in the databaseA stored procedure is a group of Transact-SQL statements compiled into a single execution plan.Accept input parameters and return multiple values in the form of

output parameters to the calling procedureContain programming statements that perform operations in the

database, including calling other procedures Return a status value to a calling procedure or batch to indicate

success or failure.


Execution Plan

The way that a statement can be physically executed is called an execution plan or a query plan


Implementing Stored Procedure

CREATE PROCEDURE proc_nameASBEGIN sql_statementENDEX:CREATE PROCEDURE STOREAS BEGINSELECT * FROM STUDENTEND


Executing Stored Procedure

EXEC/EXECUTE PROCEDURE proc_name

EX: EXEC store EXEC "My Stored Procedure"

ALTER STORED PROCEDUREEX: ALTER PROCEDURE store AS BEGIN select id, name from student END

DROP STORED PROCEDURE DROP PROCEDURE store


Parameterized Stored Procedure

CREATE PROC store @id int, @name varchar(10)ASBEGIN select name from student where id=@idEND------------------------------------------EXEC store 1, ’balaji’

EXEC store @name=‘balaji’, @id=1

VIEW THE CODE OF STORED PROCEDURE sp_helptext store create procedure store as begin select * from student end


Returning Values

CREATE PROC store @id intASBEGIN IF @id>0 RETURN 1 ELSE RETURN 0 END------------------------------------------EXEC store 1


OUTPUT parameter

CREATE PROC store @id int, @name varchar(10) OUTPUT, @adrs varchar(10) OUTPUTASBEGIN IF @id>0 SET @name=‘balaji’ SET @adrs=‘chennai’ RETURN 1 ELSE RETURN 0 END------------------------------------------DECLARE @name varchar(10), @adrs varchar(10)EXEC store 1,@name OUTPUT, @adrs OUTPUTPRINT @namePRINT @adrs


Disadvantage

If your data changes a lot then you'd have to recompile a sproc a lot because cached query plans aren't optimal for current data.

Stored procedure languages are quite often vendor-specific. If you want to switch to using another vendor's database, then you have to rewrite your stored procedures


Secured Stored Procedure

Embed sp_password/alter login in the code, as a comment

Example: CREATE PROCEDURE store

WITH ENCRYPTION AS BEGIN 'SQL statements' -- sp_password/alter login END


SET NOCOUNT

Stops the message that shows the count of the number of rows affected by aTransact SQL statement or stored procedure from being returned as part of theresult set.

These relentless interactions create overhead on the processing and inmost cases are not necessaryEXCREATE PROCEDURE STOREAS SET NOCOUNT ONBEGINSELECT * FROM STUDENTEND


Passing table valued parameters in SQL Server 2008

SQL Server 2008 introduces the ability to pass a table data type into stored proceduresand functionsCREATE TYPE STUDENTTABLETYPE AS TABLE(ID INT,SNAME VARCHAR(10),ADRS VARCHAR(10))

DECLARE @tb STUDENTTABLETYPEInsert into @tb values (5, ‘raj, ‘kovai’), (6, ‘ravi, ‘ch’), (7, ‘balu’, ‘madurai’)

CREATE PROCEDURE store(@table STUDENTTABLETYPE READONLY)AS BEGINinsert into student select * from @table where id=5END

Exec store @tb


Thank You

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Dexterity | CONFIDENTIAL 2009 MRO | Analytics | Insights 1 Stored Procedures.

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