Windows Applications

In the real world, differences in drivers and the level of ODBC support lessens the potential of ODBC:

Writing Applications

“ If I write an application for Postgres can I write it using ODBC calls to the Postgres server, or is that only when another database program like MS SQL Server or Access needs to access the data? ”

The ODBC API is the way to go. For Visual C++ coding you can find out more at Microsoft's web site or in your VC++ docs.

Visual Basic and the other RAD tools have Recordset objects that use ODBC directly to access data. Using the data-aware controls, you can quickly link to the ODBC back end database (very quickly).

Playing around with MS Access will help you sort this out. Try using File->Get External Data.

Tip: You'll have to set up a DSN first.