In-Memory Backend¶

The in-memory backend stores data in Python dictionaries, perfect for development, testing, and examples.

Features¶

Zero external dependencies
Fast operations
Automatic cleanup
Perfect for unit tests

Basic Usage¶

from restmachine_orm import Model, Field
from restmachine_orm.backends import InMemoryBackend, InMemoryAdapter
from typing import ClassVar

# Create backend
backend = InMemoryBackend(InMemoryAdapter())

class User(Model):
    model_backend: ClassVar = backend

    id: str = Field(primary_key=True)
    email: str
    name: str

# Use normally
user = User.create(id="user-1", email="alice@example.com", name="Alice")

Shared vs Isolated Backends¶

Shared Backend¶

# Shared across all models
shared_backend = InMemoryBackend(InMemoryAdapter())

class User(Model):
    model_backend: ClassVar = shared_backend

class TodoItem(Model):
    model_backend: ClassVar = shared_backend

# Both use same backend
user = User.create(id="user-1", name="Alice")
todo = TodoItem.create(id="todo-1", title="Task")

Isolated Backends¶

# Each model has own storage
class User(Model):
    model_backend: ClassVar = InMemoryBackend(InMemoryAdapter())

class TodoItem(Model):
    model_backend: ClassVar = InMemoryBackend(InMemoryAdapter())

# Completely independent storage

Clearing Data¶

backend = InMemoryBackend(InMemoryAdapter())

# Create some data
User.create(id="user-1", name="Alice")
User.create(id="user-2", name="Bob")

# Clear specific model
backend.clear(User)
assert User.where().count() == 0

# Clear all data
backend.clear()

Testing¶

The in-memory backend is ideal for tests:

import pytest

@pytest.fixture
def backend():
    backend = InMemoryBackend(InMemoryAdapter())
    yield backend
    backend.clear()  # Cleanup after test

@pytest.fixture
def user_model(backend):
    class User(Model):
        model_backend: ClassVar = backend

        id: str = Field(primary_key=True)
        name: str

    return User

def test_user_crud(user_model):
    # Test with fresh backend
    user = user_model.create(id="user-1", name="Alice")
    assert user.name == "Alice"

    retrieved = user_model.get(id="user-1")
    assert retrieved.name == "Alice"

    # Data is automatically cleaned up after test

Limitations¶

Data lost when process ends
No persistence
No transactions
Not suitable for production

The in-memory backend is designed for: - Development and prototyping - Unit tests - Examples and tutorials - Learning the ORM API

For production use, see: - DynamoDB Backend - AWS DynamoDB - OpenSearch Backend (coming soon)

Performance¶

The in-memory backend is extremely fast:

Create: O(1)
Get: O(1)
Update: O(1)
Delete: O(1)
Query: O(n) - scans all records

For performance testing, use the in-memory backend as a baseline.