PHP & MySQL® Web Development All-in-One Desk Reference for Dummies®

5.1. How MySQL and PHP Work Together

You interact with the database by passing messages to the MySQL server. As explained in Chapter 1 of this minibook, the messages are composed in the SQL language, a standard computer language understood by most database management systems.

PHP doesn't understand SQL, but it doesn't need to: PHP just establishes a connection with the MySQL server and sends the SQL message over the connection. The MySQL server interprets the SQL message, follows the instructions, and sends a return message that states its status and what it did (or reports an error if it couldn't understand or follow the instructions).

The PHP language provides functions that make communicating with MySQL extremely simple. You use PHP functions to send SQL queries to the database. You don't need to know the details of communicating with MySQL; PHP handles the details. You only need to know the SQL queries and how to use the PHP functions.

We describe the general syntax for SQL queries in Chapter 1 of this minibook. Individual specific queries are described in detail where we describe how to use MySQL for a specific purpose. For example, we describe how to create MySQL accounts in Chapter 2 in this minibook, so the SQL query for creating accounts is described at that location. On the other hand, we describe how to retrieve data from a MySQL database in Chapter 4 in this minibook, so the SQL query used for that purpose is described in detail in that chapter.