Hello To understand the problem, assume I have a model consisting of Country and SoccerTeam.
The SoccerTeam has a country = models.ForeignKey(Country).
Say, I need to find the countries having one or more related soccer
teams. I was not able to come up with a solution using the ORM, but got
to this using a list comprehension:
clist = [c for c in Country.objects.order_by('name') if
len(c.soccerteam_set.all()) > 0]
This is slow as hell. Understandable, as I have 213 countries and 4161
soccer teams in my test data.
I believe this could be done quite a lot faster using SQL.
Do I really need to use custom SQL here, or does the django ORM provide
the means to solve this problem?
Thanks,
--
Christian Joergensen | Linux, programming or web consultancy
http://www.razor.dk | Visit us at: http://www.gmta.info
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