The Structured Query Language (SQL) comprises one of the fundamental building blocks of modern database architecture. SQL defines the methods used to create and manipulate relational databases on all major platforms. At first glance, the language may seem intimidating and complex but it's really not all that bad. In a series of articles over the next few weeks we'll explore the inner workings of SQL together. By the time we're through, you'll have the fundamental knowledge you need to go out there and start working with databases!
This week, our first article in the SQL series provides an introduction to the basic concepts behind SQL and we'll take a brief look at some of the main commands used to create and modify databases. Throughout this article, please keep our goal in mind: we're trying to get the "big picture" of SQL -- not a mastery of the individual commands. We'll provide a few examples for illustrative purposes and explain the theory behind them, but don't feel frustrated if you can't write your own SQL commands after reading this article. We'll cover each of the major commands in detail in future weekly installments. If you'd like a reminder in your e-mail inbox each week when the next article is posted, please take a moment and subscribe to our newsletter.
By the way, the correct pronunciation of SQL is a contentious issue within the database community. In their SQL standard, the American National Standards Institute declared that the official pronunciation is "es queue el." However, many database professionals have taken to the slang pronunciation "sequel." The choice is yours.
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 utilize the Data Manipulation Language to insert, retrieve and modify the data contained within it. In the next two sections of this article, we'll explore DDL and DML in further detail. In future articles we'll take an in-depth look at specific SQL commands.
Now, let's take a look at the Data Definition Language. Read on!