Typical uses for stored procedures include data validation (integrated into the database) or access control mechanisms. Furthermore, stored procedures are used to consolidate and centralize logic that was originally implemented in applications. Extensive or complex processing that requires the execution of several SQL statements is moved into stored procedures, and all applications call the procedures. One can use nested stored procedures, by executing one stored procedure from within anot
Stored procedures are similar to user-defined functions (UDFs). The major difference is that UDFs can be used like any other expression within SQL statements, whereas stored procedures must be invoked using the
CALL statement.[1]Definition: Stored procedures are precompiled database queries that improve the security, efficiency and usability of database client/server applications. Developers specify a stored procedure in terms of input and output variables. They then compile the code on the database platform and make it available to aplication developers for use in other environments, such as web applications. All of the major database platforms, including Oracle, SQL Server and MySQL support stored procedures. The major benefits of this technology are the substantial performance gains from precompiled execution, the reduction of client/server traffic, development efficiency gains from code reuse and abstraction and the security controls inherent in granting users permissions on specific stored procedures instead of the underlying database tables.
Stored procedures offer several distinct advantages over embedding queries in your Graphical User Interface (GUI). Your first thought may be: "Why tolerate the added development overhead?" After seeing the advantages, you may change your mind.
Advantage 1: Stored procedures are modular. This is a good thing from a maintenance standpoint. When query trouble arises in your application, you would likely agree that it is much easier to troubleshoot a stored procedure than an embedded query buried within many lines of GUI code.Advantage 2: Stored procedures are tunable. By having procedures that handle the database work for your interface, you eliminate the need to modify the GUI source code to improve a query's performance. Changes can be made to the stored procedures--in terms of join methods, differing tables, etc.--that are transparent to the front-end interface.
Advantage 3: Stored procedures abstract or separate server-side functions from the client-side. It is much easier to code a GUI application to call a procedure than to build a query through the GUI code.
Advantage 4: Stored procedures are usually written by database developers/administrators. Persons holding these roles are usually more experienced in writing efficient queries and SQL statements. This frees the GUI application developers to utilize their skills on the functional and graphical presentation pieces of the application. If you have your people performing the tasks to which they are best suited, then you will ultimately produce a better overall application.
In short, queries are best handled via stored procedures. While the initial development overhead is greater, you will more than make up for the investment down the line.
Example:
CREATE PROCEDURE sp_GetInventory
@location varchar(10)
AS
SELECT Product, Quantity
FROM Inventory
WHERE Warehouse = @location
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