Configuration

Configuration
     Example
     Connections and Instances
     Connection Settings
         MySQL
         PDO

The default config file is located in MODPATH/database/config/database.php. You should copy this file to APPPATH/config/database.php and make changes there, in keeping with the cascading filesystem.

The database configuration file contains an array of configuration groups. The structure of each database configuration group, called an "instance", looks like this:

string INSTANCE_NAME => array(
    'type'         => string DATABASE_TYPE,
    'connection'   => array CONNECTION_ARRAY,
    'table_prefix' => string TABLE_PREFIX,
    'charset'      => string CHARACTER_SET,
),

Understanding each of these settings is important.

INSTANCE_NAME
Connections can be named anything you want, but you should always have at least one connection called "default".
DATABASE_TYPE
One of the installed database drivers. Kohana comes with "mysql" and "pdo" drivers. Drivers must extend the Database class.
CONNECTION_ARRAY
Specific driver options for connecting to your database. (Driver options are explained below.)
TABLE_PREFIX
Prefix that will be added to all table names by the query builder.
CHARACTER_SET
The character set to use for the connection with the database.

Setting Character Set won't work for PDO based connections because of incompatibility with PHP prior to 5.3.6. Use the DSN or options config instead. Example Below:

return array
(
    'default' => array
    (
        'type'       => 'PDO',
        'connection' => array(
             'options' => array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"),
        ),
    ),
);

Example

The example file below shows 2 MySQL connections, one local and one remote.

return array
(
    'default' => array
    (
        'type'       => 'mysql',
        'connection' => array(
            'hostname'   => 'localhost',
            'username'   => 'dbuser',
            'password'   => 'mypassword',
            'persistent' => FALSE,
            'database'   => 'my_db_name',
        ),
        'table_prefix' => '',
        'charset'      => 'utf8',
    ),
    'remote' => array(
        'type'       => 'mysql',
        'connection' => array(
            'hostname'   => '55.55.55.55',
            'username'   => 'remote_user',
            'password'   => 'mypassword',
            'persistent' => FALSE,
            'database'   => 'my_remote_db_name',
        ),
        'table_prefix' => '',
        'charset'      => 'utf8',
    ),
);

Connections and Instances

Each configuration group is referred to as a database instance. Each instance can be accessed by calling Database::instance. If you don't provide a parameter, the default instance is used.

// This would connect to the database defined as 'default'
$default = Database::instance();

// This would connect to the database defined as 'remote'
$remote  = Database::instance('remote');

To disconnect the database, simply destroy the object:

unset($default)

// Or

unset(Database::$instances['default']);

If you want to disconnect all of the database instances at once:

Database::$instances = array();

Connection Settings

Every database driver has different connection settings.

MySQL

A MySQL database can accept the following options in the connection array:

Type Option Description Default value
string hostname Hostname of the database localhost
integer port Port number NULL
string socket UNIX socket NULL
string username Database username NULL
string password Database password NULL
boolean persistent Persistent connections FALSE
string database Database name kohana

PDO

A PDO database can accept these options in the connection array:

Type Option Description Default value
string dsn PDO data source identifier localhost
array options Driver-specific options none
string username Database username NULL
string password Database password NULL
boolean persistent Persistent connections FALSE

The connection character set should be configured using the DSN string or options array.

If you are using PDO and are not sure what to use for the dsn option, review PDO::__construct.