I started composing a reply to your response, and then realized that I
had erroneously constructed a mental one-to-one model of the
relationship rather than one-to-many. You're absolutely right, what I
was trying to do doesn't make any sense. Whoops :)
Mike
On May 13, 2:28 pm, "Scott Moonen
Michael, I think I understand what you're getting at, given your comment
referring to the "unnecessary table and associated join". I think you want
to be able to say "ManyToOneField" in Place and have it reach back into the
Photo model and insert a NULLable "place_id" column. That's problematic f
A third alternative is to use a GenericForeignKey. Although this may
add too much complexity. Put the GenericForeignKey in a model called
PhotoTag and create a M2M relationship between it and Photo and use it
to select either a Place or a UserProfile, i.e.
class PhotoTag(models.Model)
conten
Sure. OOM relationships can typically be broken down along two
dimensions: cardinality and directionality.
cardinality: DIRECTIONALITY
--
One-to-one: ONE-WAY, BI-WAY
One-to-many: ONE-WAY, BI-WAY
Many-to-many: ONE-WAY, BI-WAY
The cardinality i
Michael, can you elaborate on what you mean by "forcing bi-directional
relationships"?
The ManyToManyField approach really is, I think, the "right" way to do it.
If you think about it, a hypothetical ManyToOneField in your case would work
almost exactly like the ManyToManyField. The join table wo
Thanks much, Scott. They both seem a bit hacky, but it gives me
something to work with anyway.
I recognize the motivation for forcing bi-directional relationships in
Django was done to keep things DRY[1], but does anyone know if there's
been any discussion about maybe relaxing this constraint?
Michael, you have two alternatives:
1. Create ManyToManyField fields in the UserProfile and Place models,
pointing to Photo. "ManyToManyField" may seem a bit odd since you really
have a many-to-one relation, but it will work as you expect, creating a join
table connecting each pair of
I have some Places and I have some Users in my database. I'd like to
be able to associate some Photos with each.
class Photo(models.Model):
# a model that represents a photo
class UserProfile(models.Model):
# has a list of Photos
class Place(models.Model):
# has a list of Pho
8 matches
Mail list logo
