To specify an ODBC data source it is necessary to specify some subset of a number of different items: driver, server, database, dbq, user, password.
There are four different ways to do this.
A DSN is a data source name. It is a reference to a previously configured specification for the type and location of a data source. The difference between System, User and File DSNs is a matter of scope and how the details are stored.
If you use the ODBC Administrator to create a DSN it will simplify your referring to a database. ODBC Administrator may be found under the Windows Control Panel / Data Sources (ODBC) or Adminstative Tools / Data Sources (ODBC)
A configuration using a DSN that you have already defined will be simply: