How to set up Django admin.TabularInline on a table with a compount key.

Question

I've essentially got two tables: Page(PK=url) and PageProperty(PK=url+name).

Here is how I have my Models set up:

class Page(model.Model):
    url   = model.CharField(primary_key=True, max_length=255, db_column='url')
    #.....

class PageProperty(model.Model):
    # table with compound key (url + name)
    url   = model.ForeignKey('Page', to_field='url', db_column='url', primary_key=True)
    name  = model.CharField(primary_key=True, max_length=20)
    value = model.TextField()

I have a ModelAdmin set up so I can Inline edit PageProperty(s) from Page. Its a legacy database and I know there's a lot of data in there. But the Admin is only showing ONE of the PagePropertys, not all.

Answer 1

I think you might need to apply the extra option to your TabularInline. Example:

class PagePropertyInline(admin.TabularInline):
    model = PageProperty
    extra = 3

You could probably do some magic to make the amount of extra items dynamic (such as the number of PageProperty objects for a given Page, but I'll leave that up to you.

I would suggest further reading on InlineModelAdmin options and Formsets.

Answer 2

Because it felt as thought a non-integer primary key was too much against the grain, I ended up buckling down and migrating the schema to use an auto generated integer pk for both tables. After that everything was smooth sailing again and the Inlines worked perfectly.