CODEWITHSUNDEEP
pythondjangotemplatesdjango-queryset
meteorainer
meteorainer

Reputation: 952

Does using django querysets in templates hit the database?

Do template value tags force django to hit the database when called against a non-context value?

For example:

{{ request.user.username }} Is the call to show the currently logged in user's username. However, something like {{ request.user.someobject_set.all }} will dump a FK traversed queryset into the template.

Does the user's someobject set get dumped into context by default, or do I need to make a context entry with a queryset in the def get_context_data of my view? And by extension, any other, non-request object that may be found by association?

The below doc shows when the querysets are evaluated in raw python, but doesn't really mention templates and views and their relationship.

https://docs.djangoproject.com/en/1.6/ref/models/querysets/#when-querysets-are-evaluated

Upvotes: 6

Views: 970

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599610

Evaluating things in the template is exactly the same as evaluating them anywhere else. When the template is rendered, the variables will be resolved, and if the object referred to requires a database lookup, then one will be carried out by that object. But this isn't the template doing anything clever, it's just telling request.user to fetch its someobject_set attribute and then calling all on it which is exactly the same as would happen in Python code.

Upvotes: 9

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