MDAC 2.5 SDK - ODBC Programmer's Reference
Chapter 6: Connecting to a Data Source or Driver

Connecting with SQLConnect

SQLConnect is the simplest connection function. It requires a data source name and accepts an optional user ID and password. It works well for applications that hard-code a data source name and do not require a user ID or password. It also works well for applications that want to control their own "look and feel" or that have no user interface. Such applications can build a list of data sources using SQLDataSources, prompt the user for data source, user ID, and password, and then call SQLConnect.