MySQL Stored Procedure Programming

Using PHP with the mysqli Extension

Before we look at how to invoke stored programs using PHP and the mysqli extension, let’s look at how we perform operations in PHP involving simple SQL statements. These operations will form the foundation for using stored programs in PHP. If you already feel very familiar with mysqli, you might want to skip forward to "Calling Stored Programs with mysqli,” later in this chapter.

Enabling the mysqli Extension

The mysqli extension ships as standard with PHP 5.0 and above, but you may need to enable it. You do this by ensuring that ext_mysqi is listed in the extensions section of your php.ini file. The ext_mysqli extension should be included in your default php.ini file, but may be commented out. In Windows, it can be found in the Windows extension section. The relevant line will look something like this:

    extension=php_mysqli.dll

On Unix or Linux, the line should look like:

    extension=mysqli.so

Connecting to MySQL

To connect to MySQL we first create an object representing a connection using the mysqli call. The mysqli call takes arguments containing the hostname, username, password, database, and port number. The mysqli_connect_errno( ) call will contain any error code associated with the connection, and mysqi_connect_error( ) will contain the error text.

In Example 13-1 we create an object—$mysqli—representing a MySQL connection, and check for any error condition.

Example 13-1. Creating a mysqli connection

# Create a connection <?php $mysqli ...