90840559 stored procedure

8/22/2019 90840559 Stored Procedure

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Stored Procedure


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Objective

At the end of the session you will be

able to know :

What are Stored Procedures? Create a Stored Procedure

Execute a Stored Procedure


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What are Stored Procedures

A stored procedure is an already

written SQL statement that is savedin the database.


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If you find yourself using the same query over and

over again, it would make sense to put it into a storedprocedure.

When you put this SQL statement in a stored

procedure, you can then run the stored procedurefrom the database's command environment using the

execcommand.


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An example is:

exec usp_displayallusers

The name of the stored procedure is "usp_displayallusers", and"exec" tells SQL Server to execute the code in the storedprocedure.

code inside the stored procedure can be something as simpleas:

SELECT * FROM USERLIST

This "select" statement will return all data in the USERLIST table.


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Writing Your First Stored Procedure

Syntax-

CREATE PROCEDURE [PROCEDURE NAME] AS

Procedure Name is the name of the stored procedure stored in

the database.

&

After the "AS" entry, you will simply enter SQL code as you would

in a regularly query.


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Example

Every stored procedure needs the words "CREATE

PROCEDURE" followed by the name you want to assign to the

stored procedure.

While not required, stored procedure names usually begin withthe prefix "usp_".

CREATE PROCEDURE usp_displayallusers

This tells the database that you are creating a stored procedure

named "usp_displayallusers".


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The next step is to think about variables. Since this is our first

stored procedure together, we wont deal with them yet.

Just keep in mind that they are usually added after the

"CREATE PROCEDURE" line.

Since we dont have variables, the next step is quite simple. Put

the word "AS" beneath the create procedure line.

CREATE PROCEDURE usp_displayallusersAS


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We are telling the database that we want to create a storedprocedure that is called "usp_displayallusers" that ischaracterized by the code that follows.

After the "AS" entry, you will simply enter SQL code as you wouldin a regularly query.

For our first, we will use a SELECT statement:

SELECT * FROM USERLIST


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your stored procedure should look like this:

CREATE PROCEDURE

usp_displayallusers

ASSELECT * FROM USERLIST

To run your stored procedure, use execcommand with SP:

exec usp_displayallusers


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More Sophisticated Stored Procedures

In addition to writing SELECT queries, you are going to want to

insert, update, and delete database records.

Also, you will probably want to pass information from outside thequery. Since inserts and updates require some sort of data input

to be useful, our first topic will be variables.

From there, we will use data stored in variables for inserts and

updates.


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Input Variables

If you are inserting new records, you will need to get the data

from somewhere.

Updating existing records also involves simply gettingthe data.

In both INSERT and UPDATE statements, it is necessary to passdata to the stored procedure.

For INSERT, UPDATE, and SELECT statements you can pass

the data to your stored procedure using variables.

Input variables are essentially "storage" for data that you want to

pass to your stored procedure.


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Variable Declaration

Inside your stored procedure, you will declare variables

at the top of the stored procedure.

You can name a variable most anything you want, though it is

best to stick with meaningful works and abbreviations.

The only real requirement is that you begin your variable with the

"@" symbol.

Here are some examples:@f_name ,

@l_name etc.


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For every data element you want to pass, you will needto declare a variable.

Declaring a variable is quite easy.

You decide on a name and a datatype (integer, text,etc.), and indicate the name and datatype at the top of

the procedure(below the "CREATE PROCEDURE" line).

First, lets create the header information that should be apart of every stored procedure.


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Example with Variables

Create Header information as-

CREATE PROCEDURE usp_adduser

/*We will put the variables in here, later

*/

We will need to create a variable for every value we may need to

pass.

The best way to address this issue is to create a variable forevery column in USERLIST.


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The list below shows the variable and the field with which it isassociated(In USERLIST Table):-

@loginlogin

@pswdpswd@f_namef_name@l_namel_name

@address_1address_1

@address_2address_2

@citycity

@statestate

@zipcodezipcode &@emailemail


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Now our stored procedure step look like


@login

@pswd@f_name@l_name@address_1@address_2@city@state@zipcode@email


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Add Datatypes to each variables

Next, add datatypes to each of the variables.

The datatype assigned to the variable should match the datatypeassigned to the corresponding column in the database,

Separate all variables (except the last one), with a comma.


@login varchar(20),

@pswd varchar(20),@f_name varchar(25),@l_name varchar(35),@address_1 varchar(30),

@address_2 varchar(30),@city varchar(30),

@state char(2),@zipcode char(10),@email varchar(50)


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ADD INSERT COMMAND TO SP

This stored procedure will add a new record to the USERLIST

table, so we should use an INSERT statement. The SQL should

be:

INSERT INTO USERLIST (login, pswd, f_name, l_name, address_1,

address_2, city, state, zipcode, email)

VALUES (sarang', sarang123', Sarang', Dalal', Srinagar',

Kalewadi', Pune,'MH', 411017', [email protected]')


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What does the entire stored procedure look like?Lets pull it all together.

CREATE PROCEDUREusp_adduser

@login varchar(20),@pswd varchar(20),@f_name varchar(25),@l_name varchar(35),@address_1 varchar(30),

@address_2 varchar(30),@city varchar(30),@state char(2),@zipcode char(10),@email varchar(50)

AS

INSERT INTO USERL IST(login, pswd, f_name, l_name, address_1,

address_2, city, state, zipcode, email)

VALUES(@login, @pswd, @f_name, @l_name, @address_1, @address_2,@city, @state, @zipcode, @email)


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Execute Stored Procedure

Now, we have a stored procedure that can accept external data.

What do we do with it? How do we get the data?

Using execcommand

The command will be:

exec usp_adduser

There is still the issue of how to get our data into the stored

procedure.

Otherwise, all those variables will be useless.

To get data into our stored procedure, simply add the information(in single quotes ' ') after the execute statement.

exec usp_adduser ' '


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To Pass many Parameters with execRemember to pass as many parameters as you have variables,otherwise SQL Server will throw an error.

Since we have ten variables, your execute statement should looklike this:

exec usp_adduser ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' '

Next, lets include the data that we will want to pass tousp_adduser.

Your execute statement will look like:

exec usp_adduser Ashish', Ashish123', Ashish', Bisen', BhootBangla Street', ' ', Pune', 'MH', '02116', [email protected]'


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Thanks

Sarang Dalal

90840559 stored procedure

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