DSN is an abbreviation for "data source name" and refers to a type of data structure that contains specific database information used by an Open Database Connectivity driver. The DSN contains information such as the directory, driver and name of the database. Certain DSN files also contain IDs and passwords.
There are three distinct types of DSN, which are user DSN, file DSN and system DSN. Both the user and system type of DSN reside within a single computer and store its information in the computer registry. When a database interacts with a user DSN, it is only able to access the user whose data is recorded in it. A system DSN allows the database to interact with any user within the specified computer.
A file DSN stores its data inside a text file that has a .dsn extension at the end. This allows users to share the file between different computers as long as the same drivers are installed on each computer. As of 2014, DSN files are commonly used by programs that use Active Server Pages or Visual Basic to retrieve information from a database.
The DSN format is also associated with other data access mechanisms such as JDBC.