How to Use Django Models for Database Management
🛠️ How to Use Django Models for Database Management
Django models are Python classes that define the structure of your database tables. They allow you to manage your database using Python code, without writing raw SQL.
✅ Step 1: Set Up a Django Project (If You Haven’t Already)
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django-admin startproject myproject
cd myproject
python manage.py startapp myapp
Add 'myapp' to your INSTALLED_APPS in settings.py.
🧩 Step 2: Create a Model
Inside myapp/models.py, define your data structure using Python classes:
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from django.db import models
class Book(models.Model):
title = models.CharField(max_length=200)
author = models.CharField(max_length=100)
published_date = models.DateField()
isbn = models.CharField(max_length=13)
price = models.DecimalField(max_digits=6, decimal_places=2)
def __str__(self):
return self.title
Each class becomes a database table, and each attribute becomes a column.
⚙️ Step 3: Apply the Model to the Database
Run the following commands to create database tables from your models:
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python manage.py makemigrations
python manage.py migrate
makemigrations: Prepares the migration files.
migrate: Applies those changes to your actual database.
✏️ Step 4: Add, Retrieve, Update, and Delete Data
➕ Add a Record
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from myapp.models import Book
book = Book(title="Django for Beginners", author="John Doe", published_date="2024-01-01", isbn="1234567890123", price=29.99)
book.save()
📥 Retrieve Records
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Book.objects.all() # Get all books
Book.objects.get(id=1) # Get book by ID
Book.objects.filter(author="John Doe") # Get books by author
🔁 Update a Record
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book = Book.objects.get(id=1)
book.price = 24.99
book.save()
❌ Delete a Record
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book = Book.objects.get(id=1)
book.delete()
🧪 Step 5: Use the Django Admin
You can manage data visually by registering your model in admin.py:
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from django.contrib import admin
from .models import Book
admin.site.register(Book)
Then create a superuser:
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python manage.py createsuperuser
Log in at http://localhost:8000/admin and manage your database records through the UI.
📘 Common Field Types
Field Type Description
CharField Short text (requires max_length)
TextField Long text
IntegerField Integer
BooleanField True/False
DateField Date only
DateTimeField Date and time
DecimalField Decimal numbers
ForeignKey Many-to-one relationship
🧠 Tips & Best Practices
Use __str__ to return a readable name in admin and shell.
Use Meta class to define ordering or table name.
Keep models clean — use managers or services for business logic.
🔚 Summary
Task Command or Code
Define Model models.Model subclass
Create Migration python manage.py makemigrations
Apply Migration python manage.py migrate
Manage Data Book.objects.create(), etc.
Use Admin Register model in admin.py
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