On 19/12/10 22:44, Andy wrote:
On Dec 19, 5:06 pm, "Jonas H."<jo...@lophus.org> wrote:
On 12/19/2010 10:20 PM, Andy wrote:
Is there a way to specify JOIN using the Django ORM? The 2 tables I'm
joining aren't related through a foreign key.
Why don't you use a relation field in your models if your models are
related?
The tables are pre-existing.
I need to do something like:
SELECT * FROM TableA JOIN TableB ON TableA.id=TableB.some_id
WHERE TableA.id=1
Is that something that can be done through the ORM?
I think so, yes. Something like this:
class ObjectA(models.Model):
id = models.IntegerField(primary_key=True, db_column='id')
class Meta:
table_name = ('TableA')
class ObjectB(models.Model):
id = models.IntegerField(primary_key=True, db_column='id')
object_a = models.ForeignKey(ObjectA, db_column='some_id)
class Meta:
table_name = ('TableB')
You can then do something like
anObjectA = ObjectA.objects.filter(id=1)[0]
objectBs = ObjectB.objects.filter(object_a=anObjectA)
objectBs is all ObjectB instances that have an objectA with serial 1
You could do this instead to avoid the anObjectA instance:
objectBs = ObjectB.objects.filter(object_a__id=1)
Hope that helps. I'm a bit confused by what you're selecting in:
> SELECT * FROM TableA JOIN TableB ON TableA.id=TableB.some_id
> WHERE TableA.id=1
What are you hoping to have returned?
Tim.
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