### Configuring backend database connections

Lithium supports a wide variety relational and non-relational databases, and is designed to allow
and encourage you to take advantage of multiple database technologies, choosing the most optimal
one for each task.

As with other `Adaptable`-based configurations, each database configuration is defined by a name,
and an array of information detailing what database adapter to use, and how to connect to the
database server. Unlike when configuring other classes, `Connections` uses two keys to determine
which class to select. First is the `'type'` key, which specifies the type of backend to
connect to. For relational databases, the type is set to `'database'`. For HTTP-based backends,
like CouchDB, the type is `'http'`. Some backends have no type grouping, like MongoDB, which is
unique and connects via a custom PECL extension. In this case, the type is set to `'MongoDb'`,
and no `'adapter'` key is specified. In other cases, the `'adapter'` key identifies the unique
adapter of the given type, i.e. `'MySql'` for the `'database'` type, or `'CouchDb'` for the
`'http'` type. Note that while adapters are always specified in CamelCase form, types are
specified either in CamelCase form, or in underscored form, depending on whether an `'adapter'`
key is specified. See the examples below for more details.

### Multiple environments

As with other `Adaptable` classes, `Connections` supports optionally specifying different
configurations per named connection, depending on the current environment. For information on
specifying environment-based configurations, see the `Environment` class.

{{{

use lithium\data\Connections;

}}}

Uncomment this configuration to use MongoDB as your default database.

{{{

// Connections::add('default', array(
// 	'type' => 'MongoDb',
// 	'host' => 'localhost',
// 	'database' => 'my_app'
// ));

}}}

Uncomment this configuration to use CouchDB as your default database.

{{{

// Connections::add('default', array(
// 	'type' => 'http',
// 	'adapter' => 'CouchDb',
// 	'host' => 'localhost',
// 	'database' => 'my_app'
// ));

}}}

Uncomment this configuration to use MySQL as your default database.

{{{

// Connections::add('default', array(
// 	'type' => 'database',
// 	'adapter' => 'MySql',
// 	'host' => 'localhost',
// 	'login' => 'root',
// 	'password' => '',
// 	'database' => 'my_app'
// ));

}}}