Django Adapter¶

Use ORMDB with Django's built-in ORM.

Installation¶

pip install django-ormdb

Setup¶

1. Configure Database¶

# settings.py
DATABASES = {
    'default': {
        'ENGINE': 'django_ormdb',
        'HOST': 'localhost',
        'PORT': 8080,
        'OPTIONS': {
            'pool_size': 10,
        },
    }
}

2. Define Models¶

# models.py
from django.db import models
import uuid

class User(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    name = models.CharField(max_length=255)
    email = models.EmailField(unique=True)
    status = models.CharField(max_length=50, default='active')
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'users'


class Post(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    title = models.CharField(max_length=255)
    content = models.TextField(blank=True, null=True)
    published = models.BooleanField(default=False)
    author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='posts')
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = 'posts'


class Comment(models.Model):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    text = models.TextField()
    post = models.ForeignKey(Post, on_delete=models.CASCADE, related_name='comments')
    author = models.ForeignKey(User, on_delete=models.CASCADE)

    class Meta:
        db_table = 'comments'

3. Sync Schema¶

python manage.py migrate

Basic Queries¶

All Objects¶

users = User.objects.all()

Filtering¶

# Equality
active_users = User.objects.filter(status='active')

# Not equal
non_banned = User.objects.exclude(status='banned')

# Greater than
adults = User.objects.filter(age__gt=18)

# Greater than or equal
adults = User.objects.filter(age__gte=18)

# Less than
young = User.objects.filter(age__lt=30)

# Contains
gmail = User.objects.filter(email__contains='@gmail')

# Starts with
admins = User.objects.filter(email__startswith='admin')

# Ends with
example = User.objects.filter(email__endswith='@example.com')

# IN
active_or_pending = User.objects.filter(status__in=['active', 'pending'])

# IS NULL
no_bio = User.objects.filter(bio__isnull=True)

# IS NOT NULL
has_bio = User.objects.filter(bio__isnull=False)

Compound Filters¶

from django.db.models import Q

# AND (chaining)
active_adults = User.objects.filter(status='active').filter(age__gte=18)

# AND (Q object)
active_adults = User.objects.filter(Q(status='active') & Q(age__gte=18))

# OR
admins_or_mods = User.objects.filter(Q(role='admin') | Q(role='moderator'))

# NOT
not_banned = User.objects.filter(~Q(status='banned'))

Ordering¶

# Ascending
users = User.objects.order_by('name')

# Descending
users = User.objects.order_by('-created_at')

# Multiple
users = User.objects.order_by('status', 'name')

Pagination¶

users = User.objects.all()[20:30]  # Skip 20, take 10

Get Single Object¶

# Get or raise DoesNotExist
user = User.objects.get(id=user_id)

# Get or None
user = User.objects.filter(email=email).first()

# Get or create
user, created = User.objects.get_or_create(
    email=email,
    defaults={'name': 'New User'}
)

Relations¶

# Single relation
posts = Post.objects.select_related('author').all()

# Multiple
posts = Post.objects.select_related('author', 'category').all()

# Access without extra query
for post in posts:
    print(post.author.name)

# Reverse relation
users = User.objects.prefetch_related('posts').all()

# Nested
users = User.objects.prefetch_related('posts__comments').all()

# Access without N+1
for user in users:
    for post in user.posts.all():
        print(post.title)

Custom Prefetch¶

from django.db.models import Prefetch

# With filter
users = User.objects.prefetch_related(
    Prefetch(
        'posts',
        queryset=Post.objects.filter(published=True).order_by('-created_at')[:5]
    )
).all()

Filtering on Relations¶

# Users with published posts
users = User.objects.filter(posts__published=True).distinct()

# Posts by active users
posts = Post.objects.filter(author__status='active')

Values and Annotations¶

Select Specific Fields¶

# Returns dictionaries
users = User.objects.values('id', 'name')

# Returns tuples
users = User.objects.values_list('id', 'name')

# Flat list of single field
emails = User.objects.values_list('email', flat=True)

Only/Defer¶

# Only load specific fields
users = User.objects.only('id', 'name')

# Exclude specific fields
users = User.objects.defer('bio', 'avatar')

Mutations¶

Create¶

# Create and save
user = User.objects.create(name='Alice', email='alice@example.com')

# Create instance then save
user = User(name='Bob', email='bob@example.com')
user.save()

# Bulk create
users = User.objects.bulk_create([
    User(name='Alice', email='alice@example.com'),
    User(name='Bob', email='bob@example.com'),
])

Update¶

# Update single
user = User.objects.get(id=user_id)
user.name = 'Alice Smith'
user.save()

# Update specific fields only
user.save(update_fields=['name'])

# Bulk update
User.objects.filter(status='pending').update(status='active')

# Update or create
user, created = User.objects.update_or_create(
    email=email,
    defaults={'name': 'Updated Name'}
)

Delete¶

# Delete single
user = User.objects.get(id=user_id)
user.delete()

# Bulk delete
User.objects.filter(status='banned').delete()

Aggregations¶

from django.db.models import Count, Sum, Avg, Min, Max

# Count
count = User.objects.filter(status='active').count()

# Aggregate
stats = Post.objects.aggregate(
    total_views=Sum('views'),
    avg_views=Avg('views'),
    min_views=Min('views'),
    max_views=Max('views'),
)

# Annotate (per object)
users = User.objects.annotate(post_count=Count('posts'))
for user in users:
    print(f"{user.name}: {user.post_count} posts")

Group By¶

# Group by field
stats = User.objects.values('status').annotate(count=Count('id'))
# [{'status': 'active', 'count': 50}, {'status': 'inactive', 'count': 10}]

Transactions¶

from django.db import transaction

# Atomic block
with transaction.atomic():
    user = User.objects.create(name='Alice', email='alice@example.com')
    Post.objects.create(title='Welcome', author=user)
    # Both committed or both rolled back

# Decorator
@transaction.atomic
def create_user_with_post(name, email, title):
    user = User.objects.create(name=name, email=email)
    Post.objects.create(title=title, author=user)
    return user

# Savepoint
with transaction.atomic():
    user = User.objects.create(name='Alice', email='alice@example.com')

    sid = transaction.savepoint()
    try:
        # Risky operation
        Post.objects.create(title='Risky', author=user)
    except:
        transaction.savepoint_rollback(sid)

    # User is still saved

Managers¶

class ActiveManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().filter(status='active')


class User(models.Model):
    # ... fields

    objects = models.Manager()  # Default
    active = ActiveManager()  # Custom

# Usage
active_users = User.active.all()

ORMDB-Specific Features¶

Access Native Client¶

from django_ormdb import get_ormdb_client

ormdb = get_ormdb_client()

# Use native ORMDB features
result = ormdb.query(GraphQuery(...))

Query Budget¶

from django_ormdb import with_budget

# Set budget for query
users = User.objects.with_budget(max_entities=100).prefetch_related('posts')

Include Soft-Deleted¶

from django_ormdb import include_deleted

# ORMDB soft deletes by default
users = User.objects.include_deleted().all()

Django Admin¶

The adapter integrates with Django admin:

# admin.py
from django.contrib import admin
from .models import User, Post

@admin.register(User)
class UserAdmin(admin.ModelAdmin):
    list_display = ['id', 'name', 'email', 'status', 'created_at']
    list_filter = ['status']
    search_fields = ['name', 'email']


@admin.register(Post)
class PostAdmin(admin.ModelAdmin):
    list_display = ['id', 'title', 'author', 'published', 'created_at']
    list_filter = ['published']
    raw_id_fields = ['author']

Migration from PostgreSQL¶

1. Update Database Settings¶

# Before
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'mydb',
        'USER': 'myuser',
        'PASSWORD': 'mypassword',
        'HOST': 'localhost',
        'PORT': '5432',
    }
}

# After
DATABASES = {
    'default': {
        'ENGINE': 'django_ormdb',
        'HOST': 'localhost',
        'PORT': 8080,
    }
}

2. Run Migrations¶

python manage.py migrate

3. Import Data¶

# Export from PostgreSQL
python manage.py dumpdata --format=json > data.json

# Import to ORMDB
python manage.py loaddata data.json

Limitations¶

Feature	Status	Notes
Raw SQL	Not supported	Use native client
`raw()`	Not supported
`extra()`	Not supported
Database functions	Partial	Basic support
F expressions	Partial	Basic support
Subqueries	Partial	Basic support
Window functions	Not supported

Next Steps¶

SQLAlchemy Adapter - Alternative Python ORM
Python Client - Direct ORMDB access
Migration Guide - Schema management

Django Adapter¶

Installation¶

Setup¶

1. Configure Database¶

2. Define Models¶

3. Sync Schema¶

Basic Queries¶

All Objects¶

Filtering¶

Compound Filters¶

Ordering¶

Pagination¶

Get Single Object¶

Relations¶

Select Related (Foreign Keys)¶

Prefetch Related (Reverse/Many)¶

Custom Prefetch¶

Filtering on Relations¶

Values and Annotations¶

Select Specific Fields¶

Only/Defer¶

Mutations¶

Create¶

Update¶

Delete¶

Aggregations¶

Group By¶

Transactions¶

Managers¶

ORMDB-Specific Features¶

Access Native Client¶

Query Budget¶

Include Soft-Deleted¶

Django Admin¶

Migration from PostgreSQL¶

1. Update Database Settings¶

2. Run Migrations¶

3. Import Data¶

Limitations¶

Next Steps¶