You could use select_related() metod.
try:
ProductType.objects.filter(product__producer__region__country=country).distinct().select_related()
or
ProductType.objects.filter(product__producer__region__country=country).select_related().distinct()
-Karsu
On 17 tammi, 14:09, "akaihola" <[EMAIL PROTECTED]> wrote:
Ok ORM gurus: my models form a foreign key "chain":
ProductType <- Product -> Producer -> Region -> Country
My view needs the list of product types for each Producer, Region and
Country. Currently I iterate all producers, regions and countries in
the view and do e.g.
country.producttypes =
ProductType.objects.filter(product__producer__region__country=country).distinct()
Then I can do {% for producttype in country.producttypes %} in the
template for every country (and region and producer).
But this method fires a whole lot of queries (10-20 ms each), and I'm
looking for an optimization. I have several solutions in mind, but none
of them are elegant. Any thoughts?
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