14.5.2012 14:50, akaariai kirjoitti:
On May 14, 2:37 pm, Jani Tiainen<rede...@gmail.com> wrote:
Hi,
I have in my database quite a bunch of a models where I do have quite
large fields and I'm using .only('pk', 'identifier') to fetch only those
two fields - mainly to make serverside natural sort for a data. Database
is legacy one and it's being used with other external programs as well
so changing it is not possible.
After sorting I just need to get slice of data and fetch rest of fields
in one query. I haven't found simple way to fetch rest of the fields in
one request.
So what I would like to do:
qs = MyModel.objects.all().only('pk', 'identifier')
list_of_models = sort_naturally(qs, 'identifier')
sublist_of_models = list_of_models[10:20]
for model in sublist_of_models:
model.fetch_all_deferred_fields()
While not totally same, how about:
for model in MyModel.objects.all(pk__in=[obj.pk for obj in
sublist_of_models]):
or maybe this will work, too:
for model in MyModel.objects.all(pk__in=sublist_of_models):
You will lose the sorting, so you will need to resort the models
again. If your model instances are changed, you will lose those
changes.
If the above isn't enough the best you can do currently is to create a
helper method which will do the merge manually.
That would probably do, and now you mentioned it I already have merge
function that can merge arbitrary dicts to models... ;)
"Dare to be stupid" like Weird Al Yankovic sings...
Of course my DB backend Oracle has limit of (I think it was 1000)
elements in parameter list so it would require additional work if
someone wants to work with more than 1k elements in a sublist.
--
Jani Tiainen
- Well planned is half done and a half done has been sufficient before...
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