Manual:$wgDBtype/en

Details
Type of database.
 * 'mssql' - MS-SQL
 * 'mysql' - or MariaDB (Will default to the newer MySQLi driver if enabled on the server.  Otherwise, falls back to the legacy MySQL driver.)
 * 'oracle' - (added in version 1.5)
 * 'postgres' - (added in version 1.7)
 * 'sqlite' - (added in version 1.13)