What is SQL?

 

Simply stated, SQL stands for Structured Query Language and is a language used to manage data stored in a relational database.

This brings us to the next question - What is a database?

 

A database is a collection of data organized in some format so that the data can be easily accessed, managed and updated. The predominant type of database is a relational database. Relational databases organize data in the form of tables. In addition, they contain queries, views and other elements to help us interact with the data.

 

In order to manage our database, we need to use a software application known as a database management system (DBMS).

 

Clear?

 

So far, we have the following terminologies:

 

1) SQL is a language
2) A database is a structured collection of data
3) A DBMS is a software that we use to manage our databases

 

With regards to DBMS, there are a large number of them available. Some are free to download and use while others are not. The most commonly used DBMS include MySQL, Oracle, Microsoft SQL Server and IBM DB2.

 

Each of these DBMS have their own versions of SQL. While this may sound intimidating, rest assured that all DBMS support the major SQL commands (such as SELECT, UPDATE, DELETE, INSERT) in a similar manner. Hence, if you know one version of SQL, it is very easy to pick up other versions.

 

In this book, we'll be using MySQL. This is one of the most popular DBMS available. Best of all, it’s free! From this point forward, whenever I mention SQL, I’m referring to the MySQL version.