Model Field Types Overview

1. Introduction

Every field in a Django model maps to a column in the database. Choosing the right field type matters — it affects what data is valid, how the database stores it, how forms render it, and how the admin displays it.

This guide covers the field types you will use in almost every project: text, numeric, date and time, boolean, and how to configure defaults, null, and blank correctly for each.

• You should already have the Page model created in the previous tutorial.
• Your .venv must be active and Django 5.2 installed.

2. Text fields

CharField

Use CharField for short text — titles, names, slugs, email addresses. Always requires max_length.

title = models.CharField(max_length=200)
slug = models.SlugField(max_length=220, unique=True)
email = models.EmailField()  # max_length=254 by default

TextField

Use TextField for long text with no length limit — blog posts, descriptions, comments. Do not use max_length on TextField — it has no effect on the database, only on form widgets.

content = models.TextField()
bio = models.TextField(blank=True)

Other text variants

url = models.URLField()            # validates as a URL, max_length=200
ip = models.GenericIPAddressField() # stores IPv4 or IPv6 addresses

3. Numeric fields

IntegerField and variants

quantity = models.IntegerField()
sort_order = models.PositiveIntegerField(default=0)
score = models.SmallIntegerField()       # -32768 to 32767
views = models.PositiveSmallIntegerField() # 0 to 32767

FloatField vs DecimalField

Use FloatField for approximate values where precision is not critical — ratings, percentages. Use DecimalField for money and anything where exact precision matters. DecimalField requires max_digits and decimal_places.

rating = models.FloatField()  # approximate, e.g. 4.75

price = models.DecimalField(max_digits=10, decimal_places=2)
# max_digits=10, decimal_places=2 allows up to 99999999.99

4. Date and time fields

published_date = models.DateField()
start_time = models.TimeField()
created = models.DateTimeField(auto_now_add=True)
updated = models.DateTimeField(auto_now=True)
scheduled = models.DateTimeField(null=True, blank=True)

• DateField — stores a date only. Maps to DATE in the database.
• TimeField — stores a time only. Maps to TIME in the database.
• DateTimeField — stores both date and time. The most commonly used of the three.
• auto_now_add=True — sets the value once when the record is first created. Cannot be changed afterward.
• auto_now=True — updates the value every time the record is saved. Useful for tracking when a record was last modified.

5. Boolean fields

is_active = models.BooleanField(default=True)
is_published = models.BooleanField(default=False)
is_verified = models.BooleanField(default=False)

BooleanField stores True or False. Always provide a default — without one, the database column has no default value and Django will raise an error when creating records without explicitly setting the field.

If you need to allow a third state — unknown or not yet set — use null=True on a BooleanField. This replaces the old NullBooleanField which was removed in Django 4.0.

consent_given = models.BooleanField(null=True, default=None)
# Can be True, False, or None (unknown)

6. null and blank — what is the difference

This is one of the most common points of confusion in Django. They sound similar but do completely different things:

• null=True — tells the database to allow NULL in the column. A database-level setting.
• blank=True — tells Django forms and validation that this field is not required. A form-level setting.

The rules are straightforward once you understand the separation:

# Required in both forms and database
title = models.CharField(max_length=200)

# Optional in forms, stores empty string in database (correct for text fields)
subtitle = models.CharField(max_length=200, blank=True)

# Optional in forms, stores NULL in database (correct for non-text fields)
published_at = models.DateTimeField(null=True, blank=True)

# Wrong — avoid null=True on CharField and TextField
# Django stores empty strings for text, not NULL
bad_example = models.CharField(max_length=200, null=True)  # avoid this

7. Setting defaults

Use default to set a value that is used automatically when none is provided:

status = models.CharField(max_length=20, default='draft')
sort_order = models.PositiveIntegerField(default=0)
is_active = models.BooleanField(default=True)
views = models.PositiveIntegerField(default=0)

You can also use a callable as a default — a function that returns a value. This is useful for dynamic defaults like the current time:

from django.utils import timezone

expires_at = models.DateTimeField(default=timezone.now)

8. Putting it together

Here is a realistic model that uses a variety of field types with the right options:

# pages/models.py

from django.db import models


class Article(models.Model):
    title = models.CharField(max_length=200)
    slug = models.SlugField(max_length=220, unique=True)
    content = models.TextField()
    excerpt = models.CharField(max_length=300, blank=True)
    views = models.PositiveIntegerField(default=0)
    is_published = models.BooleanField(default=False)
    published_at = models.DateTimeField(null=True, blank=True)
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.title

9. Next steps

You now know the most common field types and how to configure them correctly. The next step covers file and image fields — a special category that requires extra setup for handling user uploads.