What is related_name used for?

python

model

foreign-key

database-design

byNikita Barsukov·Nov 13, 2024

related_name, a tasty attribute in Django, behaves as a chef-created shortcut, enabling swift and easy access to any related objects tied to a specific Django model. It designates the label for the reverse relation tracing from the linked model all the way back to the starting line, the model of origin.

Imagine:

class Cake(models.Model): # Juicy cake model
    pass

class Slice(models.Model):
    cake = models.ForeignKey(Cake, on_delete=models.CASCADE, related_name='slices') # Each slice belongs to the cake

You can now scoop up all slices of a cake using cake.slices.all(). Without related_name, you'd have to munch on cake.slice_set.all(), which isn't quite as appetizing. By spicing up your code with related_name, it's like a sprinkle of cinnamon on your apple pie - it makes things tastier and easier to digest.

Practical use-cases: a deeper dive

Improved syntax with descriptive names

By cleverly using related_name, your code will appear cleaner, striding away from the usual _set suffix and opting for a more descriptive attribute to represent a relationship.

class Peanut(models.Model):
    pass

class Shell(models.Model):
    pass

class PeanutInShell(models.Model):
    peanut = models.ForeignKey(Peanut, on_delete=models.CASCADE, related_name='my_shells') # Our nutty friend here loves his shells

Without related_name, we would access peanut's shells through peanut.shell_set.all(). related_name accentuates code readability, clarifying the connection semantics.

Dealing with the ManyToManyField and ForeignKey

related_name comes in handy, especially when dealing with ManyToManyField and ForeignKey fields.

class Vendor(models.Model):
    stocked_items = models.ManyToManyField(Item, related_name='vendors') # This vendor's got items, lots of 'em

vendor.stocked_items.all() # Show me all stocked items for this vendor
item.vendors.all() # Who are the vendors stocking this item?

It not only tidies up your queries, but it also navigates through the complexity of multiple relationships tied to the same table.

Name your "_set" children

No more despair over clunky default names like book_author_set.

class Author(models.Model):
    pass

class Book(models.Model):
    author = models.ForeignKey(Author, on_delete=models.CASCADE, related_name='books') # Our author's written some books, many of them

author.books.all() # Look at all the books this author's written!