Outer Join Modelisation In Django
I have a many to many relationship table whith some datas in the jointing base a basic version of my model look like: class FooLine(models.Model): name = models.CharField(max_l
Solution 1:
Outer joins can be viewed as a hack because SQL lacks "navigation".
What you have is a simple if-statement situation.
forlinein someRangeOfLines:
forcolin someRangeOfCols:
try:
cell= FooVal.objects().get( col = col, line = line )
except FooVal.DoesNotExist:
cell= None
That's what an outer join really is -- an attempted lookup with a NULL replacement.
The only optimization is something like the following.
matrix = {}
forfin FooVal.objects().all():
matrix[(f.line,f.col)] = f
forlinein someRangeOfLines:
forcolin someRangeOfCols:
cell= matrix.get((line,col),None)
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