Difference between types of DSN,DSN-less and UDL

This page compares different types of DSN and mentions difference between these types of DSN and UDL.

Introduction: DSN stands for Data Source Name. It is the data structure which contains database information. DSN is required to connect with the database. The common DSN types include file DSN,system DSN and User DSN.

UDL stands for Universal Data Link. It is universal file which links to database. It is also called as Microsoft Data Link.

There are various database drivers which provides many different ways to connect. Following are the common techniques or types used to interact with database provider.

System DSNs

• It is used by anyone who has access to the system.
• Storage : System DSNs are stored in local machine section of system registry.
• Example : They are seen by all the users whoever logs into the machine.

User DSNs

• It works only for specific user on the machine.
• Storage : Current user section of system registry.
• User DSN does not show up when someone else logs into the machine except the one who created it.

File DSN

• User can store file DSNs to disk or network.
• It can be used on any machine.
• Storage : It is stored in a file and not in registry.
• Any user who has access to the file can access these file DSNs.


• NI's database toolki uses OLE DB in order to communicate with these databases.
• Using DSN, commands are translated from OLE DB to ODBC through OLE DB provider for ODBC.
• It is more efficient and recommended to use UDLs as connection method with toolkit if OLE DB provider is available for database.


• This method does not require any DSN to store connection information.
• Storage : registry, INI file, table etc.
• User is prompted during run time or stored in above storage mediums.
• Example : SQL Query Analyzer

Following table summarizes above DSN types.

DSN types

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