On computers running Microsoft Windows NT Server, Microsoft Windows NT Workstation, or Microsoft Windows 95, machine data source information is stored in the registry. Depending on which registry key the information is stored under, the data source is known as a user data source or a system data source. User data sources are stored under the HKEY_CURRENT_USER key and are available only to the current user. System data sources are stored under the HKEY_LOCAL_MACHINE key and can be used by more than one user on one machine. They can also be used by system-wide services, which can then gain access to the data source even if no user is logged on to the machine. For more information about user and system data sources, see SQLManageDataSources in Chapter 23, “Installer DLL Function Reference.”
Suppose a user has three user data sources: Personnel and Inventory, which use an Oracle DBMS; and Payroll, which uses a Microsoft SQL Server DBMS. The registry values for data sources might be:
HKEY_CURRENT_USER
SOFTWARE
ODBC
ODBC.INI
ODBC Data Sources
Personnel : REG_SZ : Oracle
Inventory : REG_SZ : Oracle
Payroll : REG_SZ : SQL Server
and the registry values for the Payroll data source might be:
HKEY_CURRENT_USER
SOFTWARE
ODBC
ODBC.INI
Payroll
Driver : REG_SZ : C:\WINDOWS\SYSTEM\SQLSRVR.DLL
Description : REG_SZ : Payroll database
Server : REG_SZ : PYRLL1
FastConnectOption : REG_SZ : No
UseProcForPrepare : REG_SZ : Yes
OEMTOANSI : REG_SZ : No
LastUser : REG_SZ : smithjo
Database : REG_SZ : Payroll
Language : REG_SZ :