Some database software directly supports Web access, with other DBMSs you will need to use an intermediary application program called middleware. Examples of middleware include ColdFusion (www.allaire.com), Active Server Pages, PHP (www.php.net), Java, and Perl (www.perl.com). Allaire's ColdFusion uses Web server Application Programming Interfaces (APIs) to interpret requests and query a database. Perl (Practical Extraction and Retrieval Language) can be used to write executable files that create queries and display HTML pages.
Middleware uses specific database drivers or relies on standards such as JDBC (Java Database Connectivity) or ODBC(Open Database Connectivity). ODBC is a set of Microsoft application programming interfaces that define how to move information to and from a PC database that supports the standard.
Most PC databases support ODBC. Middleware processes the data, formats it, and returns it to the user as an HTML document. You can check a basic article from 4/20/2000 by B. Kotek titled "Choosing a Web Database" at http://www.builder.com/Programming/ChoosingWebDB/.