SQL and SQL Server

If you have read the Introduction and the weekly description, you have seen the terms SQL and SQL Server many times. Well, here is where we define them. SQL stands for Structured Query Language. This language was created back in the mid-1970s by IBM and was originally called SEQUEL. SEQUEL was an acronym of the initials that stood for Structured English QUEry Language. The SQL used today is often pronounced "SEQUEL" as well; it is the accepted name for this method of accessing data from a database. SQL provides you with a standard method for accessing data contained within a relational database. No matter what type of database you use, SQL is the standard language to access that data within it.

The American National Standards Institute (ANSI) developed and published the standard for SQL languages back in 1989, and updated this standard in 1992 and in 1999. Having standards enables you to learn a single language and apply it to many different databases including Oracle, Access, Sybase, Visual Foxpro and SQL Server. In this book, you will be using Transact-SQL, the SQL variation associated with SQL Server, to do all the examples and workshops.

The SQL language is used to execute commands on the database server. In the case of this book, the database server that you will be working with is Microsoft SQL Server. The server is one-half of a client/server or Web-based system. The client can be either an application running on a desktop or laptop computer, or any user accessing the application across the World Wide Web. The server is responsible for physical storage of the data and the enforcement of any business rules while ensuring data integrity.

The client application is responsible for getting data from the server, formatting it, and displaying it to the user for analysis or manipulation. As an example, during a national election, you might have an application that retrieves data from a SQL Server. This server would store a table full of state voting information, and the client workstation would request that data and then build a graphical chart to display it. This division of responsibility is good because it lets each computer be specific to the task needed: You don't really need a 21-inch monitor on a SQL Server and your desktop doesn't really need 50–100GB of disk space.