Perl in a Nutshell, 2nd Edition

Chapter 12. Databases and Perl

Since one of Perl’s greatest strengths is working with text, a genuine concern is how to store data. Flat files are one possibility, but they don’t scale very well for large amounts of data. When working with lots of data, you’ll likely need database software to satisfy your capacity and performance requirements.

There are two general solutions to using databases with Perl. For simple database purposes, Database Management (DBM) will serve your needs. DBM is a library supported by many (if not all) Unix systems and many non-Unix systems as well. DBM is more efficient than flat text files because of how it packs records into the database files and the (large) size of data it can store and retrieve efficiently. Perl’s interface to your system’s DBM is based on a hash, so you can add, store, and delete data by key.

When you need to store a larger variety of data and need other goodies such as searchability on multiple records, you’ll probably need to use a database that supports SQL. To this end, you can buy a prepackaged database product such as Oracle or Sybase, or a shareware equivalent such as MySQL or PostgreSQL. For these larger database projects, you should use DBI and DBD. DBI is a module that provides a consistent interface for database solutions. DBD is a database-specific driver that translates DBI calls as needed for that database.

In this chapter, we’ll cover DBM and talk at length about DBI/DBD.