These functions allow you to access MySQL database servers. More information about MySQL can be found at http://www.mysql.com/.
Documentation for MySQL can be found at http://www.mysql.com/documentation/.
In order to have these functions available, you must compile PHP with MySQL support
By using the --with-mysql configuration option you enable PHP to access MySQL databases. If you use this option without specifying the path to MySQL, PHP will use the built-in MySQL client libraries. With PHP4 MySQL support is always eanbled; if you don't specify the configure option, the bundled libraries are used. Users who run other applications that use MySQL (for example, running PHP 3 and PHP 4 as concurrent apache modules, or auth-mysql) should always specify the path to MySQL: --with-mysql=/path/to/mysql. This will force PHP to use the client libraries installed by MySQL, avoiding any conflicts.
The behaviour of the MySQL functions is affected by settings in the global configuration file.
Tablo 1. MySQL Configuration Options
Name | Default | Changeable |
---|---|---|
mysql.allow_persistent | "On" | PHP_INI_SYSTEM |
mysql.max_persistent | "-1" | PHP_INI_SYSTEM |
mysql.max_links | "-1" | PHP_INI_SYSTEM |
mysql.default_port | NULL | PHP_INI_ALL |
mysql.default_socket | NULL | PHP_INI_ALL |
mysql.default_host | NULL | PHP_INI_ALL |
mysql.default_user | NULL | PHP_INI_ALL |
There are two resource types used in the MySQL module. The first one is the link identifier for a database connection, the second a resource which helds the result of a query.
The function mysql_fetch_array() uses a constant for the different types of result arrays. The following constants are defined:
Tablo 2. MySQL fetch constants
constant | meaning |
---|---|
MYSQL_ASSOC | Columns are returned into the array having the fieldname as the array index. |
MYSQL_BOTH | Columns are returned into the array having both a numerical index and the fieldname as the array index. |
MYSQL_NUM | Columns are returned into the array having a numerical index to the fields. This index starts with 0, the first field in the result. |
This simple example shows how to connect, execute a query, print resulting rows and disconnect from a MySQL database.