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pythonpython-3.xdjangodjango-querysetselect-for-update

How to use "select_for_update()" to get an object in Django?

As the Django Documentation says, select_for_update returns a Queryset. But get does not. Now I have a query which I am sure is going to return only one tuple. But I also need to acquire locks for this transaction. So I am doing something like:

ob = MyModel.objects.select_for_update().filter(some conditions)

Now, I need to modify some values of ob. But ob is a Queryset. This seems pretty simple, but beats me. I'm pretty new to Django. Some advice please.

Solution

  • Just call get, slice it, etc. and save as usual. The lock is in place through the transaction.

    ob = MyModel.objects.select_for_update().get(pk=1)

    Any changes are committed at the end of the transaction (which by default through 1.5 is per-request)