PHP MySQL Introduction
MySQL is the most popular open-source database system.
What is MySQL?
MySQL is a database.
The data in MySQL is stored in database objects called tables.
A table is a collections of related data entries and it consists of columns
and rows.
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 is identified
by a name (e.g. "Customers" or "Orders"). Tables contain records (rows) with
data.
Below is an example of a table called "Persons":
| LastName |
FirstName |
Address |
City |
| Hansen |
Ola |
Timoteivn 10 |
Sandnes |
| Svendson |
Tove |
Borgvn 23 |
Sandnes |
| Pettersen |
Kari |
Storgt 20 |
Stavanger |
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 from the "Persons"
table, and will return a recordset like this:
| LastName |
| Hansen |
| Svendson |
| Pettersen |
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 using
MySQL.
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