Dry ORM

Code

Result

no cache

from django.db import models

class Tag(models.Model):
    name = models.CharField(max_length=50, unique=True)

class Article(models.Model):
    title = models.CharField(max_length=100)
    content = models.TextField()
    tags = models.ManyToManyField(Tag, related_name='articles')

class Comment(models.Model):
    article = models.ForeignKey(Article, on_delete=models.CASCADE, related_name='comments')
    author = models.CharField(max_length=50)
    text = models.TextField()

def run():
    article = Article.objects.create(
        title='Django ORM Simplified',
        content='A quick intro to Django ORM.'
    )

tech = Tag.objects.create(name='Tech')
    news = Tag.objects.create(name='News')
    article.tags.add(tech, news)

Comment.objects.bulk_create([
        Comment(article=article, author='Alice', text='Very helpful!'),
        Comment(article=article, author='Bob', text='Nice and clear!')
    ])

comments_with_all_fields = Comment.objects.select_related('article').prefetch_related('article__tags')
    comments_with_only_fields = comments_with_all_fields.only('article__id')

# list(comments_with_all_fields)
    # list(comments_with_only_fields)

# What happens if we hit the omitted fields?
    for comment in comments_with_only_fields:
        print(comment.article.content)

Output

No output.

Queries

Queries Q (0)

No queries.