Django Object-Relational Mapping, commonly known as Django ORM, is a powerful tool for interacting with databases, built into Django, which is a high-level Python Web framework that allows rapid development and clean, pragmatic design. Django ORM utilizes Object-Oriented Programming (OOP) concepts to allow developers to interact with their databases, like they do with Python Objects.
To delve into the technical specifics, Django ORM is a technique that allows you to interact with your database, like you would with SQL. In other words, it’s a way to create, retrieve, update, and delete records in your database. The Django ORM is designed in a way that it can work with virtually any database backend SQL systems, including PostgreSQL, MySQL, SQLite, and others. The architecture of the ORM follows MVC and MVT design patterns for greater flexibility and control over the database layer.
A Corporate Communications Associate at Django Software Foundation Lewis (2017), states that “Instead of writing SQL statements, you’d use Python code to describe your data models (the schema of your tables) and then use that same descriptor code to query your data.” This is a prominent feature of Django ORM. For instance, if you have a model named ‘User’ and you want to get all users, instead of writing an SQL query, you could simply type: User.objects.all(), which increases readability and minimizes elusiveness in code.
Moreover, following DRY (Don’t Repeat Yourself) principle, Django ORM uses database schema defined in the models to automatically build suitable SQL query. It keeps developers away from writing repetitive SQL queries. As stated by Holovaty and Kaplan-Moss, authors of “The Django Book” (2009), “Django has this philosophy because in the past we’ve spent a disproportionate amount of time wrestling with the repetitive parts of Web development.”
Another advantage of Django ORM is that it lets you switch between several database types, without altering your codebase. Django handles the differences between the systems like PostgreSQL or MySQL internally so that you can write your code once and switch the database types as needed.
The Django ORM is also loved for its Django QuerySet tool. A queryset is a list of objects of a given model, enabling developers to filter the layouts. As demonstrated in the official Django Documentation, you can filter models based on some criteria, extending simple data retrieval functionalities to quite complex expressions.
Some other tools that are part of Django ORM and help in web development include Django DB Models, Django Fields, Django Model Fields, Django Migrations.
Thus, Django ORM brings the power of Python to your database, making data manipulation more easy, secure and robust, providing a high-level, Pythonic interface to your database.
Sources:
1. Lewis, Carlton Gibson, and Chris Palmer. “Models | Django Documentation | Django.” djangoproject.com. Django, n.d. https://docs.djangoproject.com/en/3.1/topics/db/models/.
2. Holovaty, Adrian, and Jacob Kaplan-Moss. “The Django Book”. (2009)
3. https://www.djangoproject.com/start/overview/
4. Lewis, Carlton Gibson. Django Software Foundation Corporate Communications Associate. 2017.
