MySQL FunctionsMySQL
These functions allow you to access MySQL database servers.
More information about MySQL can be found at &url.mysql;.
Documentation for MySQL can be found at &url.mysql.docs;.
Requirements
In order to have these functions available, you must compile PHP with
MySQL support.
Installation
By using the 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 enabled; 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: . This will force
PHP to use the client libraries installed by MySQL, avoiding any
conflicts.
Runtime Configuration
The behaviour of the MySQL functions is affected by settings in the
global configuration file &php.ini;.
MySQL Configuration OptionsNameDefaultChangeablemysql.allow_persistent"On"PHP_INI_SYSTEMmysql.max_persistent"-1"PHP_INI_SYSTEMmysql.max_links"-1"PHP_INI_SYSTEMmysql.default_portNULLPHP_INI_ALLmysql.default_socketNULLPHP_INI_ALLmysql.default_hostNULLPHP_INI_ALLmysql.default_userNULLPHP_INI_ALLmysql.default_passwordNULLPHP_INI_ALL
For further details and definition of the PHP_INI_* constants see
ini_set.
Here is a short explanation of the configuration directives.
mysql.allow_persistentboolean
Wether to allow
persistent connections
to MySQL.
mysql.max_persistentinteger
The maximum number of persistent MySQL connections per
process.
mysql.max_linksinteger
The maximum number of MySQL connections per process, including
persistent connections.
mysql.default_portstring
The default TCP port number to use when connecting to
the database server if no other port is specified. If
no default is specified, the port will be obtained
from the MYSQL_TCP_PORT environment
variable, the mysql-tcp entry in
/etc/services or the compile-time
MYSQL_PORT constant, in that order. Win32
will only use the MYSQL_PORT constant.
mysql.default_socketstring
The default socket name to use when connecting to a local
database server if no other socket name is specified.
mysql.default_hoststring
The default server host to use when connecting to the database
server if no other host is specified. Doesn't apply in
safe mode.
mysql.default_userstring
The default user name to use when connecting to the database
server if no other name is specified. Doesn't apply in
safe mode.
mysql.default_passwordstring
The default password to use when connecting to the database
server if no other password is specified. Doesn't apply in
safe mode.
Resource types
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.
Predefined constants
The function mysql_fetch_array uses a constant for
the different types of result arrays. The following constants are
defined:
MySQL fetch constantsconstantmeaningMYSQL_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.
MYSQL_STORE_RESULT
Specifies that the MySQL result should be buffered.
MYSQL_USE_RESULT
Specifies that the MySQL result should not be buffered.
Examples
This simple example shows how to connect, execute a query, print
resulting rows and disconnect from a MySQL database.
MySQL extension overview example
\n";
while ($line = mysql_fetch_array($result, MYSQL_ASSOC)) {
print "\t