The create database command can be used to create a new database. In this example, a database named foo is created. Notice two files are created, foo.mdf (Main Data File) and foo.ldf (Log Data File). The Main Data File contains all of the information about the foo database and the Log Data File logs all transactions and changes made to the database.
CREATE DATABASE foo ON ( NAME = foo_data, FILENAME = 'Z:\path\to\foo.mdf', SIZE = 10MB, MAXSIZE = 50MB, FILEGROWTH = 5MB ) LOG ON ( NAME = foo_log, FILENAME = 'Z:\path\to\foo.ldf', SIZE = 5MB, MAXSIZE = 25MB, FILEGROWTH = 5MB ) ;