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STORED PROCEDURES




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          STORED PROCEDURES
A stored procedure is a group of Transact-SQL statements compiled into a single
execution plan.

Stored procedures in SQL Server are similar to procedures in other programming
languages in that they can:

      Accept input parameters and return multiple values in the form of output
       parameters to the calling procedure or batch.

      Contain 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 (and the reason for failure).

You can use the Transact-SQL EXECUTE statement to run a stored procedure. Stored
procedures are different from functions in that they do not return values in place of
their names and they cannot be used directly in an expression.

The benefits of using stored procedures in SQL Server rather than Transact-SQL
programs stored locally on client computers are:

      They   allow modular programming.
      They   allow faster execution.
      They   can reduce network traffic.
      They   can be used as a security mechanism.

Stored Procedures supported by SQL Server:

SQL Server supports five types of stored procedures. They are:

System Stored Procedures (sp_)

       Many administrative and informational activities SQL Server can be performed
through system stored procedures. These system stored procedures are stored in the
Master database and are identified by the sp_prefix. They can be executed from any
database.

Local Stored Procedures

       These procedures will be created in the user database. The user who creates
the procedure will become the owner for that procedure.

Temporary Stored Procedures

       Temporary stored procedures are stored in tempdb database. They can be
used in the case where an application builds dynamic Transact-SQL statements that
are executed several times. Instead of recompiling the T-SQL statements each time,


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a temporary stored procedure can be created and compiled on the first execution,
then execute the precompiled plan multiple times. The temporary stored procedures
can be local or global.

Remote Stored Procedures

       They are legacy feature of SQL Server. Their functionality in T-SQL is limited
to executing a stored procedure on a remote SQL Server installation. The distributed
queries in SQL Server support this ability along with the ability to access tables on
linked OLEDB data sources directly from local T_SQL statements.

Extended Stored Procedures

       These are dynamic link libraries (DLLs) that SQL Server can dynamically load
and execute. These procedures run directly in the address space of SQL Server and
are programmed using the SQL Server Open Data Services API. They are identified
by the xp_prefix.

Creating a Stored Procedure

      The stored procedures can be created using the CREATE PROCEDURE
statement.

Syntax:


 CREATE PROCEDURE procedure_name
 [( @parameter1 data_type [OUTPUT] [, @parameter2 …..])]
 AS
     SQL-Statements



Example: creating a procedure to insert values into emp table.


 Create procedure empInsert
 (@eid Char,@en varchar(10),@dno int,@grd char(1),@bsal numeric(9,2),@dj datetime)
 AS
 Begin
        INSERT INTO emp VALUES(@eid,@en,@dno,@grd,@bsal,@dj)
 end


Ex: Executing the Procedure:

 EXEC empInsert E001,’sam’,10,’B’,4500,’11/3/96’




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