watch this The wheels are turning, slowly turning. home
Emergency Axiom 0.1 2005-10-17

An object-relational (sort of) database, implemented in Python, backed by SQLite, and informed by the development of Atop, and others: Axiom is still young (hardly three months have gone by since its conception), but it already supports a significant portion of the features present in the databases which shaped its development — and has for longer than not.

Axiom’s goal is to provide an efficient, non-SQL interface to an existing relational database. Unlike other libraries in this area, Axiom discourages inefficient operations (such as loading a single object at a time - possibly building it up from multiple queries against different tables): instead it encourages a style where many objects are loaded with a small, often fixed, number of queries (sometimes the number being fixed at one). This lets the underlying relational database do what it’s good at: yank data into memory out of underlying storage, perhaps based on some limiting criteria, or sorted in a particular way. From the Python side, you get genuine Python objects with Python-native attributes: Axiom is object-based, not table-, column-, or row-based. Objects stored in an Axiom database can refer to any other object stored in the same database (regardless of type - just like normal Python references), and attributes can be instances of any type Axiom natively supports (currently booleans, integers, byte strings, character strings, or timestamps). Additionally, support for new attribute types can be added by defining new attribute classes. Objects stored in an Axiom database provide a schema definition (as part of their class definition) which allows in-memory constraints to be enforced, just as they will be in the database, as well as providing necessary information for the upgrade mechanism (ie, you can change your schema without invalidating an existing database).

Of course, Axiom also integrates with common Twisted practices:

These features make it very straightforward to use Axiom in a Twisted application.

Currently, Divmod has several applications in development which use Axiom, and several more in the pipeline. Though Axiom is far from complete, even in its current form it has demonstrated its utility for a variety of applications, both client- and server-side.

It’s difficult to include a demonstration of Axiom’s abilities here: only the most trivial of database applications can reasonably fit into a blog post, yet such examples are rarely very interesting or informative. Instead, here’s a brief transcript of an interaction (in which I create myself a new user account and disable an existing account) with a database being used by a running server, using the command line tool included in Axiom, axiomatic:

$ axiomatic --dbdir cc.axiom/ userbase list | grep exarkun                        
$ axiomatic --dbdir cc.axiom/ userbase create exarkun
Enter new AXIOM password:     
Repeat to verify:     
$ axiomatic --dbdir cc.axiom/ userbase list | grep exarkun
$ axiomatic --dbdir cc.axiom/ userbase --help
Usage: axiomatic [options] userbase [options]
      --help     Display this help and exit.
    install      Install UserBase on an Axiom database
    create       Create a new user
    disable      Disable an existing user
    list         List users in an Axiom database

$ axiomatic --dbdir cc.axiom/ userbase disable exarkun
$ axiomatic --dbdir cc.axiom/ userbase list [DISABLED]

userbase is a plugin included with Axiom for user management; the axiomatic script pulls it in and makes it available to me on the command line, making the above possible.

Download Axiom 0.1, visit the project page on, or check out the Axiom wiki page.