Slide 1 of 19Session 13 Ver. 1.0 Querying and Managing Data Using SQL Server 2005 In this session,...
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Transcript of Slide 1 of 19Session 13 Ver. 1.0 Querying and Managing Data Using SQL Server 2005 In this session,...
Slide 1 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
In this session, you will learn to:Implement stored procedures
Implement functions
Objectives
Slide 2 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Stored procedures:Are created using the CREATE PROCEDURE statement
Are executed using the EXECUTE PROCEDURE statement
Syntax:
CREATE PROCEDURE proc_name
AS
BEGIN
sql_statement1
sql_statement2
END
Let’s see how…
Creating Stored Procedures
Slide 3 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Stored procedure:Is modified using the ALTER PROCEDURE statement
Syntax:
ALTER PROCEDURE proc_name
Is deleted using the DROP PROCEDURE statementSyntax:
DROP PROCEDURE proc_name
Let’s see how…
Creating Stored Procedures (Contd.)
Slide 4 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005 Just a minute
Which command will you use to modify the procedure?
Answer:ALTER PROCEDURE
Slide 5 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005 Just a minute
Which system-defined table stores the names of all the stored procedure?
Answer:sysobjects
Slide 6 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Parameterized stored procedures:Are used to pass values to the stored procedure during the run time
Involve declaring variables and passing value to it, which is defined as input parameter
Let’s see how…
Creating Parameterized Stored Procedures
Slide 7 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Stored procedure:Can also return values as output
Uses the OUPUT keyword to specify the parameter as output parameter
Syntax:
CREATE PROCEDURE procedure_name
[
{@parameter data_type} [OUTPUT]
]
AS
sql_statement [...n]
Let’s see how…
Returning Values from Stored Procedures
Slide 8 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Stored procedure:Can use the values returned by a procedure inside another procedure
That calls or executes another procedure is known as the calling procedure
That is called or executed by the calling procedure is known as the called procedure
Let’s see how…
Calling a Procedure from Another Procedure
Slide 9 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005Demo: Creating Stored Procedures
Problem Statement:You are a database developer of AdventureWorks, Inc. The Human Resource department needs to revise the payment details of the employees. You need to create a procedure that obtains the percentage value by which you need to increase the pay rate. In addition, you need to ensure that the pay is revised for only those employees whose pay rate was not revised in the last six months.
Slide 10 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Solution:To solve the preceding problem, you need to perform the following tasks:
1. Create a stored procedure.
2. Execute the stored procedure.
3. Verify the result.
Demo: Creating Stored Procedures (Contd.)
Slide 11 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Scalar functions include the following components:Function name with optional schema/owner name
Input parameter name and data type
Options applicable to the input parameter
Return parameter data type and optional name
Options applicable to the return parameter
One or more T-SQL statements
Scalar functions can be created by using the CREATE FUNCTION statement.
Creating UDFs
Slide 12 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Syntax:CREATE FUNCTION [ schema_name. ] function_name ( [ { @parameter_name [ AS ][ type_schema_name. ] parameter_data_type
[ = default ] } [ ,...n ]])RETURNS return_data_type[ WITH <function_option> [ ,...n ] ][ AS ]BEGIN function_body RETURN scalar_expressionEND[ ; ]
Let’s see how…
Creating UDFs (Contd.)
Slide 13 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Table-valued functions:Returns a table as an output, which can be derived as a part of a SELECT statement
Uses the table data type to store the set of rows
Are of following two types:Inline table-valued function
Multistatement table-valued function
Let’s see how…
Creating UDFs (Contd.)
Slide 14 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005 Just a minute
Which type of function returns a single value?
Answer:Scalar functions
Slide 15 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Problem Statement:As a database developer at AdventureWorks, Inc., you need to create a function that accepts the employee ID of an employee and returns the following details:
Employee ID
Name of the employee
Title of the employee
Number of other employees working under the employee
How will you create the function?
Demo: Creating Functions
Slide 16 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
Solution:To solve the preceding problem, you need to perform the following tasks:
1. Create a function.
2. Execute the function to verify the result.
Demo: Creating Functions (Contd.)
Slide 17 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
In this session, you learned that:A stored procedure is a collection of various T-SQL statements that are stored under one name and are executed as a single unit.
A stored procedure can be created using the CREATE PROCEDURE statement.
A stored procedure allows you to declare parameters, variables, and use T-SQL statements and programming logic.
A stored procedure provides better performance, security, and accuracy, and reduces the network congestion.
A stored procedure is a collection of various T-SQL statements that are stored under one name and are executed as a single unit.
A stored procedure can be created using the CREATE PROCEDURE statement.
Summary
Slide 18 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
A stored procedure allows you to declare parameters, variables, and use T-SQL statements and programming logic.
A stored procedure provides better performance, security, and accuracy, and reduces the network congestion.
A stored procedure accepts data through input parameters.
A stored procedure returns data through the output parameters or return statements.
A stored procedure can be executed by using the EXECUTE statement.
A stored procedure can be altered by using the ALTER PROCEDURE statement.
A user-defined function is a database object that contains a set of T-SQL statements.
The user-defined functions can return either a single scalar value or a result set.
Summary (Contd.)
Slide 19 of 19Session 13Ver. 1.0
Querying and Managing Data Using SQL Server 2005
UDFs are of two types: scalar functions and table-valued functions.
A scalar function accepts a single value and returns a single value.
A table-valued function returns a table as an output, which can be derived as a part of a SELECT statement.
Summary (Contd.)