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One of my django models has a large TextField which I often don't need to use. Is there a way to tell django to "lazy-load" this field? i.e. not to bother pulling it from the database unless I explicitly ask for it. I'm wasting a lot of memory and bandwidth pulling this TextField into python every time I refer to these objects.
The alternative would be to create a new table for the contents of this field, but I'd rather avoid that complexity if I can.
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Lazy loading means that until you perform certain actions on the queryset, such as iterating over it, the corresponding DB query won't be made. Caching means that if you re-use the same queryset, multiple DB queries won't be made.
This is because a Django QuerySet is a lazy object. It contains all of the information it needs to populate itself from the database, but will not actually do so until the information is needed.
The most important part of a model and the only required part of a model is the list of database fields it defines. Fields are specified by class attributes. Be careful not to choose field names that conflict with the models API like clean, save, or delete.
TimeStampedModel - An Abstract Base Class model that provides self-managed created and modified fields.
The functionality happens when you make the query, using the defer() statement, instead of in the model definition. Check it out here in the docs:
http://docs.djangoproject.com/en/dev/ref/models/querysets/#defer
Now, actually, your alternative solution of refactoring and pulling the data into another table is a really good solution. Some people would say that the need to lazy load fields means there is a design flaw, and the data should have been modeled differently.
Either way works, though!
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