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Lesson 3 SQL Client/Server Architecture
Objective Explain SQL Server Architecture

Explain SQL Server Architecture

Microsoft SQL Server exists for the sole purpose of performing the following tasks:
  1. Accepting information requests from the calling application.
  2. Processing the information.
  3. Returning information to the calling application.
Whereas this course is primarily concerned with how SQL Server processes information, this lesson will talk about how SQL Server accepts and returns information.

The calling application

The application that makes and receives requests for information is called the client application, or simply, the client. The client makes requests to SQL Server, which is known simply as the server. This type of architecture is known as client/server. Usually, the client and the server are located on different computers.

Connecting with the Server

For the client and server to be able to communicate with each other, a common communication method, called a protocol, or a net-library, must be in place. Otherwise, information cannot be exchanged over a connection. This would be similar to a telephone conversation in which neither of the parties spoke the same language.

Role of the net-library

The net-library resides on both the client and server sides, in order to translate information on both ends. The net-library.is specified at the network level, and can be any standard network protocol.

Changing protocols on the client side

If you wish to install or use a different protocol on the client side, you must use the Client Network Utility by choosing
             
Start-->Programs-->Microsoft SQL Server 2012-->Client Network Utility. 

The following illustration shows what the Client Network Utility looks like:
Client Network Utility

Changing protocols on the server side

If you with to install or use a different protocol on the server side, you must use the Server Network Utility by choosing
Start-->Programs-->Microsoft SQL Server 2012-->Server Network Utility. 

The following illustration shows what the Client Network Utility looks like:

Server Network Utility

Putting it all together


So, how does it all fit together? Well, your application makes a call through an Application Programming Interface, or API, to a provider (if your application is OLE DB ), a driver (if your application is ODBC), or a DB-library (if your application is DB-library). This call is then passed through the network using the Client-side Net-library, across your LAN or WAN, to the server-side Net-library, and finally on to SQL Server. The request is processed and returned in the reverse order.