I love Django's aggregation framework. It very successfully abstracts the common aggregration tasks into a Pythonic syntax that sits extremely well with the rest of the ORM, and the documentation explains it all without a single reference to SQL.

But sometimes that very abstraction gets in the way of ...

View commentss.

One of the features I quite missed when I first moved from Komodo to Textmate as my main editor was autocompletion. Although I didn't use it very much, it was occasionally useful to be reminded of the methods available on a class, without having to look up the documentation ...

View commentss.

So, I've learned my lesson. When I first set up this blog I said at great length that I'd prefer using Django's built-in commenting system than the third-party Disqus service that Mingus uses by default.

Well, after a week of trying to stop a flood of spam ...

View commentss.

Occasionally I need to create a temporary model within a Django application.

The most recent occasion for this was a one-off management command I was writing to import some data from a legacy system. The old database, for some reason, eschewed foreign keys in favour of char fields in a ...

View commentss.

One common database operation that isn't supported out of the box by Django's ORM is create_or_update - in other words, given a set of parameters, either update an existing object or create a new one if there isn't one already.

The naive implementation is to do a get ...

View commentss.

My last post talked about how to follow reverse generic relations efficiently. However, there's a further potential inefficiency in using generic relations, and that's the forward relationship.

If once again we take the example of an Asset model with a GenericForeignKey used to point at Articles and Galleries ...

View commentss.

I've previously talked about how to make reverse lookups more efficient using a simple dictionary trick. Today I want to write about how this can be extended to generic relations.

At its heart, a generic relationship is defined by two elements: a foreign key to the ContentType table, to ...

View commentss.

One of the requirements for the new Heart website we've just launched was to allow users to personalise their location to one of 33 radio stations across the country. For various reasons, this meant rewriting all the links on the page, dynamically, depending on the user's location setting ...

View commentss.

One of the main sources of unnecessary database queries in Django applications is reverse relations.

By default, Django doesn't do anything to follow relations across models. This means that unless you're careful, any relationship can lead to extra hits on the database. For instance, assuming MyModel has a ...

View commentss.

I like the Mac as a development environment most of the time, but occasionally some things annoy me.

One of these niggles is the way that the tab title in Terminal changes when you SSH to an external server, but doesn't change back when you close the connection. So ...

View commentss.