Installed apps management in Django - Step-by-Step Execution

Concept Flow - Installed apps management

Start: settings.py

↓

Locate INSTALLED_APPS list

↓

Add or remove app names

↓

Save settings.py

↓

Run server or migrate

↓

Django loads apps accordingly

↓

Apps available for use in project

Django reads the INSTALLED_APPS list in settings.py to know which apps to load and manage.

Execution Sample

Django

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'myapp',
]

This code lists apps Django will load, including built-in and a custom app 'myapp'.

Execution Table

Step	Action	INSTALLED_APPS Content	Effect
1	Read settings.py	['django.contrib.admin', 'django.contrib.auth', 'myapp']	Django knows which apps to load
2	Add 'blog' app	['django.contrib.admin', 'django.contrib.auth', 'myapp', 'blog']	Django will load 'blog' app too
3	Remove 'myapp'	['django.contrib.admin', 'django.contrib.auth', 'blog']	'myapp' no longer loaded
4	Save settings.py	No change	Settings updated
5	Run migrations	Apps loaded as per list	Database updated for loaded apps
6	Start server	Apps loaded	Project runs with specified apps
7	Exit	No change	Process ends

💡 Process stops after server starts with apps listed in INSTALLED_APPS

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
INSTALLED_APPS	['django.contrib.admin', 'django.contrib.auth', 'myapp']	['django.contrib.admin', 'django.contrib.auth', 'myapp', 'blog']	['django.contrib.admin', 'django.contrib.auth', 'blog']	['django.contrib.admin', 'django.contrib.auth', 'blog']

Key Moments - 2 Insights

Why does removing an app from INSTALLED_APPS stop Django from loading it?

Because Django reads INSTALLED_APPS to know which apps to load; if an app is not listed (see execution_table step 3), Django ignores it.

What happens if you add an app to INSTALLED_APPS but forget to run migrations?

The app's database tables might not be created, causing errors when the app tries to access the database (refer to execution_table step 5).

Visual Quiz - 3 Questions

Look at the execution_table at step 2, what change happens to INSTALLED_APPS?

A An app named 'myapp' is removed

B No change to INSTALLED_APPS

C An app named 'blog' is added

D All apps are removed

💡 Hint

Check the INSTALLED_APPS Content column at step 2 in execution_table

At which step does Django stop loading 'myapp'?

A Step 1

B Step 3

C Step 2

D Step 6

💡 Hint

Look at the INSTALLED_APPS Content column in execution_table rows

If you add a new app but do not save settings.py, what happens?

A Django ignores the new app

B Django loads the new app anyway

C Django crashes immediately

D Django partially loads the app

💡 Hint

Refer to the flow: changes must be saved in settings.py before Django loads apps

Concept Snapshot

INSTALLED_APPS is a list in settings.py where you add app names.
Django loads only apps listed here.
Add or remove apps by editing this list.
Save changes and run migrations if needed.
Restart server to apply changes.

Full Transcript

In Django, the INSTALLED_APPS list in settings.py tells the framework which apps to load. When you add an app name to this list, Django includes it in the project. Removing an app name stops Django from loading it. After editing this list, you save the file and run migrations if the app uses database models. Finally, restarting the server applies the changes. This process ensures Django manages only the apps you want active in your project.