Most serious Web applications have an underlying database. On a UNIX system this might be MySQL, PostgresSQL, Oracle, DB2, or another database package. On VMS, it could be Oracle Server, Oracle (formerly Digital) Rdb, Cache, or Mimer. But I'm only going to talk about Rdb first, because that's the database that I have experience with; second, because that database has only fairly recently acquired most of the Web connection tools needed; and, third, because there's all kinds of documentation available for tools such as Oracle Developer and you don't need this book to get the information. Some of the concepts discussed in this chapter may be useful with other databases, but the specifics are all for Rdb.

Without any special database connectivity software you can still communicate databases by having your program write database update or query scripts, spawning them, and parsing the results. This is both ugly and slow, but it could be good enough for very occasional use. (You could even write Datatrieve scripts, taking advantage of Datatrieve's ability to write HTML output to skip the parsing step.) Here are the special tools available to connect Rdb to the Web.

15.1 Rdb Web Agent

Don't confuse this with the Oracle Web Cartridge, which works only if you're running the Oracle Web Server. The Rdb Web Agent, which can run under any of the Web servers, is a CGI package that stands between the Web server and the database, invoking a program that's written as a stored procedure in the...