Stored procedures are a batch of SQL statements that can be executed in a couple of ways. Most major DBMs support stored procedures; however, not all do. You will need to verify with your particular DBMS help documentation for specifics. As I am most familiar with SQL Server I will use that as my samples.
To create a stored procedure the syntax is fairly simple:
CREATE PROCEDURE <owner>.<procedure name> <Param> <datatype> AS <Body>
So for example:
CREATE PROCEDURE Users_GetUserInfo @login nvarchar(30)=null AS SELECT * from [Users] WHERE ISNULL(@login,login)=login
A benefit of stored procedures is that you can centralize data access logic into a single place that is then easy for DBA's to optimize. Stored procedures also have a security benefit in that you can grant execute rights to a stored procedure but the user will not need to have read/write permissions on the underlying tables. This is a good first step against SQL injection.
Stored procedures do come with downsides, basically the maintenance associated with your basic CRUD operation. Let's say for each table you have an Insert, Update, Delete and at least one select based on the primary key, that means each table will have 4 procedures. Now take a decent size database of 400 tables, and you have 1600 procedures! And that's assuming you don't have duplicates which you probably will.
This is where using an ORM or some other method to auto generate your basic CRUD operations has a ton of merit.
A stored procedure is a set of precompiled SQL statements that are used to perform a special task.
Example: If I have an
Employee ID Name Age Mobile --------------------------------------- 001 Sidheswar 25 9938885469 002 Pritish 32 9178542436
First I am retrieving the
Create Procedure Employee details As Begin Select * from Employee End
To run the procedure on SQL Server:
Execute Employee details --- (Employee details is a user defined name, give a name as you want)
Then second, I am inserting the value into the Employee Table
Create Procedure employee_insert (@EmployeeID int, @Name Varchar(30), @Age int, @Mobile int) As Begin Insert Into Employee Values (@EmployeeID, @Name, @Age, @Mobile) End
To run the parametrized procedure on SQL Server:
Execute employee_insert 003,’xyz’,27,1234567890 --(Parameter size must be same as declared column size)
Employee table the
Name column's size must be
A stored procedure is a group of SQL statements that has been created and stored in the database. A stored procedure will accept input parameters so that a single procedure can be used over the network by several clients using different input data. A stored procedures will reduce network traffic and increase the performance. If we modify a stored procedure all the clients will get the updated stored procedure.
Sample of creating a stored procedure
CREATE PROCEDURE test_display AS SELECT FirstName, LastName FROM tb_test; EXEC test_display;
Advantages of using stored procedures
A stored procedure allows modular programming.
You can create the procedure once, store it in the database, and call it any number of times in your program.
A stored procedure allows faster execution.
If the operation requires a large amount of SQL code that is performed repetitively, stored procedures can be faster. They are parsed and optimized when they are first executed, and a compiled version of the stored procedure remains in a memory cache for later use. This means the stored procedure does not need to be reparsed and reoptimized with each use, resulting in much faster execution times.
A stored procedure can reduce network traffic.
An operation requiring hundreds of lines of Transact-SQL code can be performed through a single statement that executes the code in a procedure, rather than by sending hundreds of lines of code over the network.
Stored procedures provide better security to your data
Users can be granted permission to execute a stored procedure even if they do not have permission to execute the procedure's statements directly.
In SQL Server we have different types of stored procedures:
System-stored procedures are stored in the master database and these start with a
sp_ prefix. These procedures can be used to perform a variety of tasks to support SQL Server functions for external application calls in the system tables
Example: sp_helptext [StoredProcedure_Name]
User-defined stored procedures are usually stored in a user database and are typically designed to complete the tasks in the user database. While coding these procedures don’t use the
sp_ prefix because if we use the
sp_ prefix first, it will check the master database, and then it comes to user defined database.
Extended stored procedures are the procedures that call functions from DLL files. Nowadays, extended stored procedures are depreciated for the reason it would be better to avoid using extended stored procedures.
Generally, a stored procedure is a "SQL Function." They have:
-- a name CREATE PROCEDURE spGetPerson -- parameters CREATE PROCEDURE spGetPerson(@PersonID int) -- a body CREATE PROCEDURE spGetPerson(@PersonID int) AS SELECT FirstName, LastName .... FROM People WHERE PersonID = @PersonID
This is a T-SQL focused example. Stored procedures can execute most SQL statements, return scalar and table-based values, and are considered to be more secure because they prevent SQL injection attacks.
A stored procedure is mainly used to perform certain tasks on a database. For example
A stored procedure is used to retrieve data, modify data, and delete data in database table. You don't need to write a whole SQL command each time you want to insert, update or delete data in an SQL database.
Think of a situation like this,
A stored procedure is nothing but a group of SQL statements compiled into a single execution plan.
Example: creating a stored procedure
SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE PROCEDURE GetEmployee @EmployeeID int = 0 AS BEGIN SET NOCOUNT ON; SELECT FirstName, LastName, BirthDate, City, Country FROM Employees WHERE EmployeeID = @EmployeeID END GO
Alter or modify a stored procedure:
SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER PROCEDURE GetEmployee @EmployeeID int = 0 AS BEGIN SET NOCOUNT ON; SELECT FirstName, LastName, BirthDate, City, Country FROM Employees WHERE EmployeeID = @EmployeeID END GO
Drop or delete a stored procedure:
DROP PROCEDURE GetEmployee
A stored procedure is a named collection of SQL statements and procedural logic i.e, compiled, verified and stored in the server database. A stored procedure is typically treated like other database objects and controlled through server security mechanism.
A stored procedure is a precompiled set of one or more SQL statements which perform some specific task.
A stored procedure should be executed stand alone using
A stored procedure can return multiple parameters
A stored procedure can be used to implement transact
In a DBMS, a stored procedure is a set of SQL statements with an assigned name that's stored in the database in compiled form so that it can be shared by a number of programs.
The use of a stored procedure can be helpful in
Providing a controlled access to data (end users can only enter or change data, but can't write procedures)
Ensuring data integrity (data would be entered in a consistent manner) and
Improves productivity (the statements of a stored procedure need to be written only once)