Data Source Name

In computing, a data source name (DSN, sometimes known as a database source name though data sources are not limited to databases) are data structures used to describe a connection to a data source. Most commonly used in reference to ODBC, DSNs may also be defined for JDBC and other data access mechanisms.

DSN attributes may include, but are not limited to:

The system administrator of a client machine creates a separate DSN for each relevant data source.

Standardizing DSNs offers a level of indirection that various applications (for example: Apache/PHP and IIS/ASP) can take advantage of in accessing shared data sources.

Contents

Types of data source name

Two kinds of DSN exist:

These are further broken down into

Misuse of the term

The term DSN is sometimes mistakenly used in place of connection string. A connection string typically fully describes a data source, while a DSN typically relies on some external system resources and/or configuration files.

Example of use

Software (e.g., Crystal Reports, Microsoft Excel, PHP, Perl, Python, Ruby) users can submit CRUD (Create, Read, Update, Delete) queries to a data source by establishing a connection to the DSN.

ASP (VBScript) code to open a DSN connection might look like the following:

Dim DatabaseObject1
Set DatabaseObject1 = Server.CreateObject("ADODB.Connection")
DatabaseObject1.Open("DSN=DSNname;")

In PHP using the PEAR::DB package to open a connection without an external DSN (a "DSN-less connection", i.e., using a Connection String), the code might resemble the following:

require_once("DB.php");
//$dsn = "<driver>://<username>:<password>@<host>:<port>/<database>";
$dsn = "mysql://john:pass@localhost:port/my_db";
$db = DB::connect($dsn);

See also