With PHP, you can connect to and manipulate databases.
MySQL is the most popular database system used with PHP.
The data in MySQL is stored in tables. A table is a collection of related data, and it consists of columns and rows.
Databases are useful when storing information categorically. A company may have a database with the following tables:
A query is a question or a request.
We can query a database for specific information and have a recordset returned.
Look at the following query (using standard SQL):
The query above selects all the data in the "LastName" column from the "Employees" table.
To learn more about SQL, please visit our SQL tutorial.
If you don't have a PHP server with a MySQL Database, you can download MySQL
for free here:
One great thing about MySQL is that it can be scaled down to support embedded database applications. Maybe it is because of this many people think that MySQL can only handle small and medium-sized systems.
The truth is that MySQL is the de-facto standard database system for web sites with HUGE volumes of both data and end users (like Friendster, Yahoo, and Google).
Look at http://www.mysql.com/customers/ for an overview of companies using MySQL.
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