What is Client-Server?

Let's start off by saying that Microsoft Access is a file based database as opposed to a client-server database. All requests for data are processed on the client by Jet (Jet being the database engine behind the Access interface) compared to a database like SQL Server, where all requests for data are processed on the server by the database engine, then passed to the client. For example, if you place a copy of an Access database on a network server and then provide say twenty users with front-end applications, all processing of data will take place on each user's PC independently of the database backend on the server. Just think of the network traffic this causes as each user downloads data to the local PC! Using the Client-Server architecture, processing is carried out on the database server, in this case SQL Server, leading to improvements in speed and the reduction of data being passed along the wire to the client PC. However, as we shall see, moving up to bigger and better software does not always lead to performance improvements, and, at times, can even see a performance drop as developers continue to build applications as if they where using Access, for example, not restricting the records retrieved from the server. Using SQL Server, you could be pulling thousands of records across the network as opposed to hundreds. In addition, when you use the common front-end backend setup with Access and have multiple users, you also have the problem of many different processes writing to a single database file; a failure in any process can collapse the entire application.