Django Models all queries and commands

 # Basic Queries

MyModel.objects.create(field1=value1, field2=value2)

MyModel.objects.all()

MyModel.objects.filter(field=value)

MyModel.objects.get(field=value)

MyModel.objects.exclude(field=value)

# Querying with Conditions

MyModel.objects.filter(field1=value1).filter(field2=value2)

from django.db.models import Q

MyModel.objects.filter(Q(field1=value1) | Q(field2=value2))

from django.db.models import Count

MyModel.objects.annotate(num_related=Count('related_model'))

from django.db.models import Avg

MyModel.objects.aggregate(Avg('field'))

# Ordering and Slicing

MyModel.objects.order_by('field')

MyModel.objects.order_by('-field')

MyModel.objects.all()[:5]

# Advanced Queries

MyModel.objects.select_related('related_model')

MyModel.objects.prefetch_related('related_model')

MyModel.objects.values('field1', 'field2')

MyModel.objects.values_list('field1', flat=True)

# Existence Checks

MyModel.objects.filter(field=value).exists()

# Counting and Aggregating

MyModel.objects.count()

MyModel.objects.aggregate(Sum('field'))

# Updates and Deletes

MyModel.objects.filter(field=value).update(field2=new_value)

MyModel.objects.filter(field=value).delete()

# Other Useful Queries

MyModel.objects.distinct('field')

MyModel.objects.raw('SELECT * FROM myapp_mymodel WHERE field = %s', [value])

# Complex Queries

from django.db.models import OuterRef, Subquery

subquery = MyModel.objects.filter(field=OuterRef('related_field'))

MyModel.objects.filter(field__in=Subquery(subquery.values('id')))

# Aggregation Examples

MyModel.objects.aggregate(

    avg_field=Avg('field'),

    total_field=Sum('field'),

    count_field=Count('id')

)

# Using F Expressions

from django.db.models import F

MyModel.objects.filter(field=value).update(field2=F('field2') + 1)

# Performing Transactions

from django.db import transaction

with transaction.atomic():

    MyModel.objects.create(field=value)

    MyModel.objects.create(field=value2)

## All commands for django app

# Basic Commands

python manage.py runserver              # Start development server

python manage.py startproject <name>   # Create new Django project

python manage.py startapp <app_name>   # Create new app

python manage.py check                 # Check for issues

python manage.py diffsettings          # Show differences from default settings

# Database & Migrations

python manage.py makemigrations         # Create migration files

python manage.py migrate                # Apply migrations

python manage.py showmigrations         # List migrations and status

python manage.py sqlmigrate <app> <id>  # Show SQL for a migration

python manage.py flush                  # Reset DB (delete all data)

python manage.py inspectdb              # Generate models from existing DB

python manage.py dbshell                # Open DB shell

# User Management

python manage.py createsuperuser        # Create admin user

python manage.py changepassword <user>  # Change user password

# Testing & Debugging

python manage.py test                   # Run tests

python manage.py shell                  # Django Python shell

# Static & Media Files

python manage.py collectstatic          # Collect static files

python manage.py clearsessions          # Clear expired sessions

# Deployment Support

python manage.py check --deploy         # Check deployment best practices

# Custom Commands

python manage.py <your_command>         # Run custom management command