MySQL Introduction

What is MySQL?

MySQL is a database. A database defines a structure for storing information. MySQL is the most popular open source database server.

In a database, there are tables. Just like HTML tables, database tables contain rows, columns, and cells.

Databases are useful when storing information categorically. A company may have a database with the following tables:

"Employees", "Products", "Customers" and "Orders".

Database Tables

A database most often contains one or more tables. Each table has a name (e.g. "Customers" or "Orders"). Each table contains records (rows) with data.

Below is an example of a table called "Persons":

LastName      FirstName     Address         City 

Henry         Wilson       Ol, Timoteivn  Chicago 
Sebastian     Roy          23, Sandnes    Las Vegas
Alice         John         20, Stavanger  Paris

The table above contains three records (one for each person) and four columns (LastName, FirstName, Address, and City).

Queries

A query is a question or a request.

With MySQL, we can query a database for specific information and have a recordset returned.

Look at the following query:

SELECT LastName FROM Persons

The query above selects all the data in the LastName column in the Persons table, and will return a recordset like this:

LastName
Henry
Sebastain 
Alice

Download MySQL Database

If you don't have a PHP server with a MySQL Database, you can download MySQL for free here: http://www.mysql.com/downloads/index.html

Facts About MySQL Database

One great thing about MySQL is that it can be scaled down to support embedded database applications. Perhaps it is because of this reputation that many people believe that MySQL can only handle small to medium-sized systems.

The truth is that MySQL is the de-facto standard database for web sites that support huge volumes of both data and end users (like Friendster, Yahoo, Google). Look at http://www.mysql.com/customers/ for an overview of companies that uses MySQL.

The free MySQL Database is very often used with PHP.