Programming the Perl DBI

Database Proxying

Database proxying is the ability to forward database queries to a database, using an intermediate piece of software, the proxy, and return the results from those queries without the client program having any database drivers installed.

For example, a common use for a database proxy is for a client program located on a Unix machine to query a Microsoft Access database located on a Windows machine. Suppose the Unix machine has no ODBC software or drivers installed and thus doesn’t know anything about ODBC. This means that it needs to forward any queries to a proxy server that does know about ODBC and the Access database. The proxy server then issues the query and gathers the results, which it then passes back to the client program for processing.

This functionality is extremely powerful, as it allows us to access databases on virtually any operating system from any other operating system, provided that they are both running Perl and the DBI. There is an additional benefit in terms of software distribution: if client PCs used Perl scripts to access an Oracle database located on a central Unix server, you don’t have to undergo a potentially complex Oracle client software installation. DBI proxy capabilities make this client software unnecessary.

Furthermore, you can automatically add ``network awareness'' to types of databases that could never otherwise support such a thing. For example, with the DBI proxy capabilities, you could run a Perl script on a Windows machine ...