How to Create a Model in Django: Simple Guide

In Django, you create a model by defining a class that inherits from django.db.models.Model. Inside this class, you add attributes using field types like CharField or IntegerField to represent database columns.

Syntax

A Django model is a Python class that inherits from models.Model. Each attribute in the class represents a database field with a specific type.

• class ModelName(models.Model): defines the model.
• field_name = models.FieldType(...) defines a database column.
• Common field types include CharField for text and IntegerField for numbers.

python

from django.db import models

class ModelName(models.Model):
    field_name = models.FieldType(options)

Example

This example shows a simple Book model with a title, author, and publication year. It demonstrates how to define fields and their types.

python

from django.db import models

class Book(models.Model):
    title = models.CharField(max_length=100)
    author = models.CharField(max_length=50)
    year_published = models.IntegerField()

    def __str__(self):
        return f"{self.title} by {self.author} ({self.year_published})"

Common Pitfalls

Common mistakes when creating Django models include:

• Forgetting to inherit from models.Model, which makes the class not a model.
• Not specifying required field options like max_length for CharField.
• Using Python reserved words as field names.
• Not running migrations after creating or changing models.

python

from django.db import models

# Wrong: missing inheritance
class Car:
    name = models.CharField(max_length=50)

# Right:
class Car(models.Model):
    name = models.CharField(max_length=50)

Quick Reference

Field Type	Description	Common Options
CharField	Text field with max length	max_length (required)
IntegerField	Integer number	None
BooleanField	True/False value	default
DateField	Date value	auto_now, auto_now_add
ForeignKey	Link to another model	to, on_delete

Key Takeaways

Always inherit your model class from django.db.models.Model.

Define fields with appropriate field types and required options like max_length.

Run migrations after creating or updating models to apply changes to the database.

Avoid using Python reserved words as field names to prevent errors.

Use the __str__ method to make model instances readable in admin and shell.