How to View Raw SQL Queries Executed by Django

Last Updated : 22 Aug, 2024

The most important thing while working on Django is to understanding the executed SQL queries running in the background. It is really important from the perspective that, with the help of these SQL queries, one can tune the performance of the database, find the bottlenecks, and troubleshoot the problems appropriately. The three major approaches to viewing raw SQL queries that Django runs will continue.

How to View Raw SQL Queries Executed by Django

1. Django Debug Toolbar

The Django Debug Toolbar is a popular third-party package that provides a rich debugging toolbar for Django projects. Among other features, this one is enabled for displaying the SQL queries performed by Django.

We follow these steps to apply the Django Debug Toolbar

Step 1: We install the Django Debug Toolbar for our project:

python -m pip install django-debug-toolbar

Step 2: We add 'debug_toolbar' to our 'INSTALLED_APPS' setting in 'settings.py'

INSTALLED_APPS = [
    # ...
    "debug_toolbar",
    # ...
]

Step 3: We need to add some urls for debug toolbar to work in the main url file.

project/urls.py

Python

from django.urls import include, path
from debug_toolbar.toolbar import debug_toolbar_urls

urlpatterns = [
    # ... the rest of your URLconf goes here ...
] + debug_toolbar_urls()

Step 4: Add the debug tool base to middleware

The most of the operation are done in middlware itself, so we need to add debug toolbar middle ware in the settings.py file

settings.py

Python

MIDDLEWARE = [
    # ...
    "debug_toolbar.middleware.DebugToolbarMiddleware",
    # ...
]

We can place the middleware at the top of all middleware. However, it must come after any other middleware that encodes the response’s content, such as GZipMiddleware.

Step 5: Updated INTERNAL_IPS

INTERNAL_IPS is a list containing IP addresses. Debug toobar will be shown for all the IP addresses mentioned in the INTERNAL_IPS list. We only want to use this feature during development phase, so, we can add "localhost" and "127.0.0.1" to INTERNAL_IPS.

INTERNAL_IPS = [
    "localhost",
    "127.0.0.1",
    # ...
]

Now, we are all done with the configuration and can view the debug toolbar console at all endpoints.

Step 6: Create a model, view and run the server

For a basic view to the toolbar console, we have created a simple Book model and a book list view.

test_app/models.py

Python

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()

    def __str__(self) -> str:
        return self.title

test_app/views.py

Python

from django.shortcuts import render

def book_list(request):
    books = Book.objects.all()
    return render(request, 'test_app/book_list.html', {'books': books})

test_app/template/test_app/book_list.html

HTML

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Debug ToolBar Guide</title>
</head>
<body>
    <h1>Book List</h1>

    <ul>
    {% for book in books %}
        <li>
            <strong>
                {{ book.title }}
            </strong>
            <small>
                ({{ book.published_date }})
            </small>
        </li>
    {% endfor %}
    </ul>
    
</body>
</html>

Run the development server:

python manage.py runserver

Output:

Screenshot-2024-08-20-102034 — Book List

In the toolbar, select "SQL" to reveal the SQL queries executed.

You can See the Raw SQL Queries Django in Debug Toolbar

In our view, we are executing only one SQL query that is perfectly recorded by the debug toolbar.

Screenshot-2024-08-20-102154 — Debug toolbar

2. Using the 'query' Attribute of QuerySet

Yet another way to view raw SQL queries is to use the query attribute of a QuerySet object. The following method comes in handy when we want to inspect the SQL query generated by a specific QuerySet.

Python

from django.db.models import Q
qs = User.objects.filter(Q(first_name='John') | Q(last_name='Doe'))
print(qs.query)

Output:

SELECT * FROM myapp_mymodel WHERE name = 'John' OR email = '[email protected]'

This will return the raw SQL generated from a QuerySet.

3. Using connection.queries

Django provides an interface to access the executed SQL through the attribute connection.queries. This technique is pretty handy if we want to inspect all of the SQL queries executed by Django.

Python

from django.db import connection

# Execute some queries
User.objects.all()
Book.objects.filter(title='Django')

# Print the executed queries
print(connection.queries)

Output:

[ 
{'sql': 'SELECT * FROM myapp_mymodel WHERE id = 1', 'time': '0.0003'}, 
{'sql': 'SELECT * FROM myapp_mymodel WHERE name = \'John\'', 'time': '0.0005'},
{'sql': 'INSERT INTO myapp_mymodel (name, email) VALUES (\'Jane\', \'[email protected]\')', 'time': '0.0012'}
]

This will print a list of dictionaries, each dictionary containing the executed SQL query and its execution time.

Conclusion

In this article, we have demonstrated three different ways to see the raw SQL queries which Django is running. We can use Django Debug Toolbar, the query attribute of the QuerySet, or connection.queries to know the SQL queries being executed by Django and really fine-tune the performance of your database.

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How to View Raw SQL Queries Executed by Django