Slide 1 of 19Session 13 Ver. 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 13 Ver. 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 13 Ver. 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 statement Syntax: DROP PROCEDURE proc_name Let’s see how… Creating Stored Procedures (Contd.)

Slide 4 of 19Session 13 Ver. 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 13 Ver. 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 13 Ver. 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 13 Ver. 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 [ data_type} [OUTPUT] ] AS sql_statement [...n] Let’s see how… Returning Values from Stored Procedures

Slide 8 of 19Session 13 Ver. 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 13 Ver. 1.0 Querying and Managing Data Using SQL Server 2005 Demo: 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 13 Ver. 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 13 Ver. 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 13 Ver. 1.0 Querying and Managing Data Using SQL Server 2005 Syntax: CREATE FUNCTION [ schema_name. ] function_name ( [ [ AS ][ type_schema_name. ] parameter_data_type [ = default ] } [,...n ] ] ) RETURNS return_data_type [ WITH [,...n ] ] [ AS ] BEGIN function_body RETURN scalar_expression END [ ; ] Let’s see how… Creating UDFs (Contd.)

Slide 13 of 19Session 13 Ver. 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 13 Ver. 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 13 Ver. 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 13 Ver. 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 13 Ver. 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 13 Ver. 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 13 Ver. 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.)