the djb way



The cdb package may be used to create and manipulate cdb's: "constant databases".

A cdb is a persistent-store file format developed by Daniel J. Bernstein, designed for fast access to keyed data. It is commonly known as a "hash" database --and also as an "associative array"-- where the physical location of a particular record may be directly computed from the value of the key.

cdb's are most suitable for applications where the data remains relatively constant, keys are known, and data access is frequent and generally read-only. That is, things like a user/password database, a chart of accounts for a general ledger, or a periodic table of the elements. On the other hand, you generally would not use a cdb to record minute-to-minute changes in meteorological data.

We've seen many .cdb's along the djb way, including:

A qmail installation may include even more:

cdb's are used in these instances because they are fast and reliable. The cdb package described here let's us easily develop and use cdb's in our own applications.

Copyright © 2003, 2004, Wayne Marshall.
All rights reserved.

Last edit 2004.02.24, wcm.