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Structured Query Language (SQL)


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Most large-scale databases use the Structured Query Language (SQL) to facilitate user and administrator interactions. This language offers a flexible interface for databases of all shapes and sizes.

You might not see it, but SQL’s always there!

The first important point to make is that [em]all[/em] database transactions are made in SQL, whether you realize it or not. Nowadays, there are a large number of graphical user interfaces (GUIs) that simplify database administration tasks. If you're a SQL Server user, you may be familiar with tools like Enterprise Manager.

MySQL users may use any of a number of front ends. There are also quite a few third-party applications that interact with different databases (in fact, many of these can work with multiple database platforms simultaneously.) Did you ever wonder how these applications work? That’s right! They use SQL! The front-end translates your mouse clicks and text entries into SQL and then “speaks” to the database in the universal language of SQL.

Flavors of SQL

SQL comes in many flavors. Oracle databases utilize their proprietary PL/SQL. Microsoft SQL Server makes use of Transact-SQL. However, all of these variations are based upon the industry standard ANSI SQL. In our tutorial series, we'll stick to ANSI-compliant SQL commands that will work on any modern relational database system.


SQL commands can be divided into two main sublanguages. The Data Definition Language (DDL) contains the commands used to create and destroy databases and database objects. After the database structure is defined with DDL, database administrators and users can use the Data Manipulation Language to insert, retrieve and modify the data contained within it.

Is SQL Knowledge Required?

Do you need to know SQL? Not necessarily. If you’re comfortable using the graphical front end tools, they might be more than sufficient to meet your needs. However, most serious database administrators and developers rely upon custom-written SQL code to ensure that their transactions meet user requirements in the most efficient manner possible. In any event, you should at least have a passing familiarity with this important language that forms the bedrock of relational databases.

Learning More

If you're ready to dive in and learn more about SQL, keep browsing this site. I suggest starting with the SQL Fundamentals article. You also may wish to take our free Learning SQL e-course.
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