The table below outlines the database and storage connectors available for Joomla! as well as which version of Joomla they became available in.
To make a connector available in Joomla's installer or global configuration manager, you will need to ensure the PHP library is installed (E.g. for PHP5 and MySQL the php5-mysql library would need to be installed).
Microsoft SQL Server
Microsoft SQL Azure
PHP Data Objects (PDO)*
PHP Data Objects is a database abstraction layer and is shipped with PHP 5.1+.