Why execute stored procedures is faster than SQL query from a script?

Question

In fact, if I call the stored procedures from my application, I need a connection to my DB.

So, why calling a \"stored procedures\" should be faster than \"passing a

Answer 1

Because every time you pass a query string to SQL Server the code has to be compiled etc, stored procedures are already compiled and ready to run on the server.

Also you are sending less data over the network although this is generally a minimal impact anyway.

EDIT: As a side note stored procedures have other benefits.

1) Security - Since the actual query is stored on the server you are not transmitting this over the network which means anyone intercepting your network traffic does not gain any insight into your table structure. Also a well designed SP will prevent injection attacks.

2) Code seperation, you keep your database code in your database and your application code in your application, there is very little crossover and I find this makes bug fixing a lot nicer.

3) Maintainability and Code Reuse, you can reuse a procedure many times without having to copy paste the query, also if you wish to update the query you just have to update it in one place.

4) Decreased network traffic. As mentioned above this may not be an issue for most people but with a large application you can significantly reduce the ammount of data being transferred via your network by switching to using stored procedures.