DSN stands for Data Source Name. It is a configuration setting that provides a consistent and convenient way to identify and connect to a data source, such as a database or file, within a computer system. DSNs are commonly used in the context of ODBC (Open Database Connectivity) and OLE DB (Object Linking and Embedding, Database) technologies.
Here are some key points about DSNs:
Purpose: A DSN serves as a logical name or alias for a data source. Instead of specifying the connection details (such as server address, port, database name, authentication credentials) every time an application needs to connect to a data source, a DSN can be used to encapsulate and manage these settings.
Configuration: DSNs are typically configured and managed using specific tools provided by the database management system or the ODBC/OLE DB driver. These tools allow you to define the connection parameters, such as the database server address, port number, database name, and authentication details, and associate them with a DSN.
System DSN vs. User DSN: DSNs can be categorized as system DSNs or user DSNs, based on their availability and scope. System DSNs are created and managed at the system level, making them accessible to all users on the computer. User DSNs, on the other hand, are specific to an individual user and are only available within their user account.
DSN-less Connections: While using DSNs provides a convenient way to manage connection settings, it is also possible to establish database connections without relying on DSNs. This approach, known as DSN-less connections, involves specifying the connection parameters directly in the application code or configuration files, eliminating the need for separate DSN configurations.
Flexibility and Portability: DSNs offer flexibility and portability by decoupling the connection details from the application code. This allows you to change the connection settings associated with a DSN without modifying the application code. It also simplifies deployment and maintenance, as the same application code can be used with different DSN configurations.
DSN and ODBC/OLE DB: DSNs are commonly used with ODBC and OLE DB technologies. In the case of ODBC, the DSN is used by the ODBC driver manager to locate and load the appropriate driver and establish the database connection. Similarly, with OLE DB, the DSN is used by the OLE DB provider to identify and connect to the data source.
Connection String: When using DSNs, applications typically provide the DSN name as part of the connection string. The connection string contains additional parameters and options required to establish the connection, such as the username, password, and specific settings supported by the database or driver.
DSNs provide a convenient and centralized way to manage and configure database connections. By using DSNs, applications can achieve greater flexibility, portability, and ease of maintenance when connecting to various data sources through ODBC or OLE DB.