Meanings of user DSN, system DSN, and file DSN in ODBC

ODBC (Open Database Connectivity, ODBC) means open database Interconnection

DSN (data source name) is the data source name

ODBC contains user DSN, system DSN, and file DSN.Three data sources.

The meaning of user DSN is to save the corresponding configuration to the Windows registry. It is only for the user who creates the DSN to log on. (User DSN is saved in the Registry under HKEY_CURRENT_USER)

The meaning of the system DSN is to save the corresponding configuration to the registry of the system, which is different from the user DSN that allows users who have logged on to the Service to use. (The system DSN is saved in the Registry HKEY_LOCAL_MACHINE)

The file DSN indicates that the corresponding configuration is saved to a file on the hard disk. The file DSN allows all users who have logged on to the Service to use it, it also provides database DSN access support for users who have not logged on to the service. In addition, the file DSN can be copied to other machines (files can be shared within the network ). In this way, you can directly use the DSN created on other machines without making any changes to the system registry.