Introduction to SQL

For those of you who have just started designing web sites, you are probably well versed in the basics of the HTML programming language. HTML is an easy language to learn. Most beginning web designers are self-taught. They learn HTML through simple online tutorials. HTML, however, is not the only language of cyberspace. There is a lot more to web programming than meets the eye.

HTML only takes care of the front end. There are many other languages and specifications that handle the back end. Javascript, Visual Basic, PHP and a host of other programming languages make a web site come to life. One such important and valuable language is Standard Query Language (SQL), which is the focus of this article.

SQL is the primary language for accessing and interacting with databases running on the backend of a web site. Whenever you use a website to access information, you are using SQL to extract the information you want from the database where the information is stored. SQL works with almost all database programs, such as MS Access, DB2, Informix, MS SQL Server, Oracle, and Sybase.

Databases generally consist of tables. Tables consist of records. Each record in a table contains certain information, separated by columns. For example, a dating website where people can post their profiles would probably consist of a table holding a record of each person who has a membership. In each record, there would be different columns containing information about that particular person. There would likely be a column for height, weight, age, marital status, and other personal information.

When someone using that dating website searches for a profile that matches certain criteria that they are looking for in a potential mate, their query is converted into an SQL statement. That SQL statement interacts with the database, pulls out the profiles that match the search criteria, and then returns the search results to the user. SQL statements consist of commands such as Select, Update, Insert, and Delete. Here is an example of an SQL statement:

SELECT Name,Height,Weight from BODY;

This statement will retrieve all of the data from the Name, Height, and Weight columns contained within the table called Body. SQL is not case sensitive, but the example listed above uses caps to make the statement easier to read. SQL is used not only to find certain things within a table, but to add and remove data as well.

SQL is perhaps the most important programming language of the web. After all, the primary reason why we use the internet is to obtain information about a certain topic. Almost all websites have a database where this information is stored, and SQL enables us to find what we are looking for. All web designers need to understand how to create a simple database and how to create simple SQL statements to make that database accessible to the user. Since the syntax of the language is not complicated, it is easy to learn SQL using online tutorials. If you prefer, you can enroll in SQL courses offline at a local college or computer programming institute. Either way, you need to learn SQL because it is perhaps the most vital programming language of the world wide web.

Author: Jim Pretin