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, a data source name (DSN, sometimes known as a database source name though data sources are not limited to databases
Database management system
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s 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:
name of the data source
directory of the data source
name of a driver which can access the data source
user ID for data access (if required)
user password for data access (if required)
The system administrator of a client machine creates a separate DSN for each relevant data source.
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) can take advantage of in accessing shared data sources.
Types of data source name
Two kinds of DSN exist:
Machine DSNs - stored in collective configuration files (e.g., /etc/odbc.ini, ~/.odbc.ini) and/or system resources (e.g., Windows Registry HKLM\Software\ODBC\odbc.ini)
File DSNs - stored in the filesystem with one DSN per file
These are further broken down into
System DSNs - accessible by any and all processes and users of the system, stored in a centralized location (e.g., /etc/odbc.ini, /etc/odbc_file_dsns/)
User DSNs - accessible only by the user who created the DSN, stored in a user-specific location (e.g., ~/.odbc.ini, ~/odbc_file_dsns/)
Misuse of the term
The term DSN is sometimes mistakenly used in place of connection string
Connection string
In computing, a connection string is a string that specifies information about a data source and the means of connecting to it. It is passed in code to an underlying driver or provider in order to initiate the connection...
. 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.
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) code to open a DSN connection might look like the following:
Dim DatabaseObject1
Set DatabaseObject1 = Server.CreateObject("ADODB.Connection")
DatabaseObject1.Open("DSN=DSNname;")
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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:
