Module 12 Implementing Stored Procedures

8/9/2019 Module 12 Implementing Stored Procedures

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Module 12:Implementing StoredProcedures

Vidya Vrat Agarwal. | MCT, MCSD


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Introduction to Stored Procedures

Creating, Executing, and Modifying Stored Procedures

Using Parameters in Stored Procedures

Executing Extended Stored Procedures

Overview


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Introduction of Stored Procedures

A stored procedure is a named collection of Transact-SQL statements thatis stored on the server. Stored procedures are a method ofencapsulating repetitive tasks that executes efficiently.

A precompiled collection of Transact-SQL statements stored under a nameand processed as a unit. SQL Server-supplied stored procedures arecalled system stored procedures.

Named Collections of Transact-SQL Statements

Encapsulate Repetitive Tasks

Five Types (System, Temporary, Local, Extended and Remote)

Accept Input Parameters and Return Values

Return Status Value to Indicate Success or Failure


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Initial Processing of Stored Procedures

Entries into sysobjectsand syscomments tables

Entries into sysobjectsand syscomments tables

Compiled plan placed inprocedure cache

Compiled plan placed inprocedure cacheCompilation

Compilation

Optimization

Optimization

Creation

CreationCreation

Execution(first time

or recompile)

ExecutionExecution(first time(first time

or recompile)or recompile)

Parsing

Parsing


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Advantages of Stored Procedures

Share Application Logic

Shield Database Schema Details

Provide Security Mechanisms

Improve Performance

Reduce Network Traffic


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Creating Stored Procedures

Create in Current Database with the CREATEPROCEDURE Statement

Can Nest to 32 Levels

Use sp_help to Display Information

Use library

GO

CREATE PROC[EDURE] overdue_books

AS

SELECT *

FROM dbo.loan

WHERE due_date < GETDATE()

GO

EXEC overdue_books


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Guidelines for Creating Stored Procedures

dbo User Should Own All Stored Procedures

One Stored Procedure for One Task

Create, Test, and Debug on Server

Avoid sp_ Prefix in Stored Procedure Names

Use Same Connection Settings for All Stored Procedures

Minimize Use of Temporary Stored Procedures


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Input parameters allow information to be passed into astored procedure. To define a stored procedure that acceptsinput parameters, you declare one or more variables asparameters in the CREATE PROCEDURE statement.

The maximum number of parameters in a stored procedureis 1024.

Parameters are local to a stored procedure. The sameparameter names can be used in other stored procedures.


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Using Input Parameters

Create Proc Pname@myname varchar(20) = Vidyaasprint 'My Name is' + ' ' + @myname

Exec Procedure Name [Parameter]

Exec pname Vidya My Name is Vidya

Exec pname Vidya Vrat My Name is Vidya Vrat

Exec pname My Name is Vidya

Pname My Name is Vidya

Step 1

Step 2


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create proc pst

@sid as char(8)

as

select * from student

where student_id=@sid

exec pst '1111111'

1111111 Antonius Purba Male 20 Medan


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Executing Stored Procedures with Input Parameters

Passing Values by Reference

Passing Values by Position

EXEC addadult 'LaBrie', 'Linda', null,

'Dogwood Drive', 'Sacramento', 'CA',

'94203', null

EXEC addadult 'LaBrie', 'Linda', null,

'Dogwood Drive', 'Sacramento', 'CA',

'94203', null

EXEC addadult

@firstname = 'Linda',

@lastname = 'LaBrie',

@street = 'Dogwood Drive',

@city = 'Sacramento',@state = 'CA',

@zip = '94203'

EXEC addadult

@firstname = 'Linda',

@lastname = 'LaBrie',

@street = 'Dogwood Drive',

@city = 'Sacramento',

@state = 'CA',

@zip = '94203'


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Updating Data

UPDATE statement

NOCOUNT option

CREATE PROCEDURE p_UpdateCategory(

@CategoryID int = null,

@CategoryName varchar(50)

)

AS

SET NOCOUNT ONUPDATE Categories

SET Category = @CategoryName

WHERE CategoryID = @CategoryID

CREATE PROCEDURE p_UpdateCategory

(

@CategoryID int = null,

@CategoryName varchar(50)

)

AS

SET NOCOUNT ONUPDATE Categories

SET Category = @CategoryName



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Inserting Data

INSERT Statement

CREATE PROCEDURE p_InsertCustomer(

@FName varchar(50),

@LName varchar(50)

)

AS

SET NOCOUNT ON

INSERT INTO Customers (FirstName, LastName)

VALUES (@FName, @LName)

CREATE PROCEDURE p_InsertCustomer(

@FName varchar(50),

@LName varchar(50)

)

AS

SET NOCOUNT ONINSERT INTO Customers (FirstName, LastName)

VALUES (@FName, @LName)


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Deleting Data

DELETE Statement

CREATE PROCEDURE p_DeleteCategory

(@CategoryID int = null

)

AS

SET NOCOUNT ON

DELETE FROM Categories


CREATE PROCEDURE p_DeleteCategory

(

@CategoryID int = null

)

AS

SET NOCOUNT ON

DELETE FROM Categories



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Returning Values with Output Parameters

CREATE PROCEDURE mathtutor

@m1 smallint,

@m2 smallint,

@result smallint OUTPUT

AS

SET @result = @m1 * @m2

DECLARE @answer smallint

EXECUTE mathtutor 5, 6, @answer OUTPUT

SELECT 'The result is: ' , @answer

The result is: 30

CREATE PROCEDURE mathtutor

@m1 smallint,

@m2 smallint,

@result smallint OUTPUT

AS

SET @result = @m1 * @m2

DECLARE @answer smallint

EXECUTE mathtutor 5, 6, @answer OUTPUT

SELECT 'The result is: ' , @answer

The result is: 30

Results of StoredProcedure

Results of StoredResults of StoredProcedureProcedure

Executing StoredProcedure

Executing StoredExecuting StoredProcedureProcedure

Creating StoredProcedure

Creating StoredCreating StoredProcedureProcedure


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OUTPUT Parameter

Stored procedures can return information to the calling storedprocedure or client with output parameters (variablesdesignated with the OUTPUT keyword).

By using output parameters, any changes to the parameterthat result from the execution of the stored procedure can be

retained, even after the stored procedure completesexecution.

To use an output parameter, the OUTPUT keyword must bespecified in both the CREATE PROCEDURE and EXECUTEstatements.

If the keyword OUTPUT is omitted when the stored procedureis executed, the stored procedure still executes, but it doesnot return a value. i.e. Shows NULL .


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Increase SQL Server Functionality

Are Programmed Using Open Data Services API

Can Include C and C++ Features Can Be Added to the master Database Only

EXEC master..xp_cmdshell 'dir c:\mssql7'


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Return Statement

The RETURN statement exits from a query or storedprocedure unconditionally. It also can return an integerstatus value (return code).

A return value of 0 indicates success; 1-99 indicates error


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Return statement

create proc ps

@age int

as

if (@age > 28) return (1)

select * from student

where age >=@age

return(0)

declare @status int

exec @status= ps 20

select @status


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Check Your Understanding.


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Q.1 What is Stored Procedure.?


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Q.2. How many types of stored procedures are availablewith SQL server. ?


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Q.3. You should use sp_ Prefix in Stored ProcedureNames.?

1. Yes

2. No


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Q.4. Return Value, Indicates Success or Failure.?

1. True

2. False


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Q.5. The maximum number of parameters in a storedprocedure is _____________ .


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Q.6. What will be the output of the following :

EXEC master..xp_cmdshell 'dir c:\mssql7


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Q.7. Name the five stored procedures availablewith SQL Server.


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Q.8. What are the Mistakes in the given Create Proccommand.

cREATE pROC Pnamemyname varchar(20) = PIDelasprint 'My Name is' + ' ' + @myname


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Q.9. The same parameter names can be used inother stored procedures.

1. True

2. False


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Q.10. If the keyword OUTPUT is omitted when the storedprocedure is executed, the stored procedure still executes,but it does not return a value.

1. True

2. False


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Q.11. A junior SQL Server programmer asks you for help. Sheexecuted a SQL statement on the server from her computer.Before she could verify that it executed properly, she lost networkconnectivity. From your computer, you access the server and usethe @@error system function. It returns a value of 0. What doesthat indicate about the last statement executed on the server?

1. It stopped executing due to the loss of connectivity.

2. It logged an error number 0.

3. It logged an error with a severity level of 0.

4. It is executed successfully.


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Q.12. You are the system administrator of a productiondatabase server. You want to create a storedprocedure to automate certain administrative tasks on

the Finance database. You do not want the storedprocedure to be used in other databases. What type ofstored procedure should you use?

1. System

2. Local3. Global temporary

4. Extended.


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Review

Introduction to Stored Procedures

Creating, Executing, and Modifying Stored Procedures

Using Parameters in Stored Procedures



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It is not enoughto aimyou mustHit .

Thank You.

Module 12 Implementing Stored Procedures

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