Category Software Related Stories Handling Data with SQL -- 11/17/98 Next: What is a Relational Database System?

Continued from Introduction

SQL is a special-purpose, nonprocedural language that supports the definition, manipulation, and control of data in relational database management systems. It's a special-purpose language, because you can use it only for handling databases; you can't write general-purpose applications with it. (To write an application, you have to embed SQL in some other language, and it's frequently used that way.) That's why SQL is also known as a data sublanguage. A sublanguage can be used with application languages, but it is not a full-fledged application language. Also, a full-featured application language usually includes semantics for procedures, whereas SQL is nonprocedural. It doesn't specify how something should be done, it just specifies what should be done. In other words, SQL is concerned with results rather than procedures.

By far the most important feature of SQL is that it provides access to relational databases. That's so fundamental to SQL that many people think the terms SQL database and relational database are synonymous. But as you'll soon see, they're not. In fact, the SQL-92 standard doesn't even mention the term relation.

Next: What is a Relational Database System?

Published as PC Tech Feature in the 11/3/98 issue of PC Magazine.

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