Can "list_display" in a Django ModelAdmin display attributes of ForeignKey fields?
I have a Person
model that has a foreign key relationship to Book
, which has a number of fields, but I'm most concerned about author
(a standard CharField).
With that being said, in my PersonAdmin
model, I'd like to display book.author
using list_display
:
class PersonAdmin(admin.ModelAdmin):
list_display = ['book.author',]
I've tried all of the obvious methods for doing so, but nothing seems to work.
Any suggestions?
Solution 1:
As another option, you can do look ups like:
class UserAdmin(admin.ModelAdmin):
list_display = (..., 'get_author')
def get_author(self, obj):
return obj.book.author
get_author.short_description = 'Author'
get_author.admin_order_field = 'book__author'
Since Django 3.2 you can use display()
decorator:
class UserAdmin(admin.ModelAdmin):
list_display = (..., 'get_author')
@display(ordering='book__author', description='Author')
def get_author(self, obj):
return obj.book.author
Solution 2:
Despite all the great answers above and due to me being new to Django, I was still stuck. Here's my explanation from a very newbie perspective.
models.py
class Author(models.Model):
name = models.CharField(max_length=255)
class Book(models.Model):
author = models.ForeignKey(Author)
title = models.CharField(max_length=255)
admin.py (Incorrect Way) - you think it would work by using 'model__field' to reference, but it doesn't
class BookAdmin(admin.ModelAdmin):
model = Book
list_display = ['title', 'author__name', ]
admin.site.register(Book, BookAdmin)
admin.py (Correct Way) - this is how you reference a foreign key name the Django way
class BookAdmin(admin.ModelAdmin):
model = Book
list_display = ['title', 'get_name', ]
def get_name(self, obj):
return obj.author.name
get_name.admin_order_field = 'author' #Allows column order sorting
get_name.short_description = 'Author Name' #Renames column head
#Filtering on side - for some reason, this works
#list_filter = ['title', 'author__name']
admin.site.register(Book, BookAdmin)
For additional reference, see the Django model link here
Solution 3:
Like the rest, I went with callables too. But they have one downside: by default, you can't order on them. Fortunately, there is a solution for that:
Django >= 1.8
def author(self, obj):
return obj.book.author
author.admin_order_field = 'book__author'
Django < 1.8
def author(self):
return self.book.author
author.admin_order_field = 'book__author'
Solution 4:
Please note that adding the get_author
function would slow the list_display in the admin, because showing each person would make a SQL query.
To avoid this, you need to modify get_queryset
method in PersonAdmin, for example:
def get_queryset(self, request):
return super(PersonAdmin,self).get_queryset(request).select_related('book')
Before: 73 queries in 36.02ms (67 duplicated queries in admin)
After: 6 queries in 10.81ms