Models in Django - potatoscript/django GitHub Wiki

🧒 What is a Django Model?

A model in Django is a blueprint for your data.
It tells Django:

• ✅ What kind of data you want to save (like name, age, photo…)
• ✅ What type each piece of data is (text, number, image…)
• ✅ How to store and retrieve that data from the database

You don’t need to touch SQL directly — Django takes care of that for you! 🙌

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🧱 Step-by-Step: Creating and Using Models

Let’s build a model step by step. Think of it like creating your own collectible card system! 🃏

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🛠️ 1. Define Your Model in models.py

📄 Inside your app (like myapp/models.py):

from django.db import models

class Toy(models.Model):
    name = models.CharField(max_length=100)
    category = models.CharField(max_length=50)
    age_limit = models.IntegerField()
    is_available = models.BooleanField(default=True)
    added_on = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return f"{self.name} ({self.category})"

🧠 What’s happening?

• CharField = text
• IntegerField = number
• BooleanField = true/false
• DateTimeField = time added
• __str__ = what shows in admin panel

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🧹 2. Register the Model in admin.py

So Django knows we want to manage this model in the admin panel:

📄 myapp/admin.py

from django.contrib import admin
from .models import Toy

admin.site.register(Toy)

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📋 3. Make Migrations (Tell Django About Changes)

In the terminal:

python manage.py makemigrations

📦 This prepares the blueprint.

Then run:

python manage.py migrate

🧱 This builds the actual table in your database!

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🔑 4. Create a Superuser (If Not Already Done)

python manage.py createsuperuser

• Username: admin
• Email: [email protected]
• Password: ********

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🚪 5. Log in to Django Admin

Run your server:

python manage.py runserver

Go to:
http://127.0.0.1:8000/admin/

Login with your superuser, and voilà!
You’ll see the “Toy” model you created — ready to add, edit, and delete toy entries! 🎉

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🧪 6. Play with the Data from Python (Shell Time!)

Run:

python manage.py shell

Then:

from myapp.models import Toy

# Create a new toy
t1 = Toy(name="Rubik's Cube", category="Puzzle", age_limit=8)
t1.save()

# See all toys
Toy.objects.all()

# Find specific toys
Toy.objects.filter(category="Puzzle")

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🔁 Full Example

Here’s a full Django app model setup:

📂 mytoys/

models.py
admin.py
views.py

📄 models.py

from django.db import models

class Toy(models.Model):
    name = models.CharField(max_length=100)
    color = models.CharField(max_length=30)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    in_stock = models.BooleanField(default=True)
    added = models.DateField(auto_now_add=True)

    def __str__(self):
        return f"{self.name} - ${self.price}"

📄 admin.py

from django.contrib import admin
from .models import Toy

@admin.register(Toy)
class ToyAdmin(admin.ModelAdmin):
    list_display = ('name', 'price', 'color', 'in_stock', 'added')
    list_filter = ('in_stock', 'color')
    search_fields = ('name',)

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📌 Model Field Types (Like LEGO Blocks 🧱)

Field Type	What It Does	Example
CharField	Small text	Name, Category
TextField	Long text	Description, Bio
IntegerField	Whole number	Age, Quantity
BooleanField	True/False	Available, Published
DateTimeField	Date and time	Created on, Updated at
DecimalField	Decimal numbers	Price, Ratings
ImageField	Upload image	Profile pic, Product image
ForeignKey	Connect to another model	Author of Post, Owner of Toy

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🎯 What Can You Do with Models?

• Create forms from models automatically 📝
• Query data easily (.filter(), .exclude(), .get())
• Use model data in your views and templates
• Save and update data from user input

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