When you learn web programming, it can feel like you’re learning two languages at once: SQL for your database and Python for your logic. Some students find it hard to transition between these two, which makes coding take longer. The Django ORM (Object-Relational Mapper) comes to the rescue here.
You don’t have to write complicated database queries; instead, you may work with your data like you would with regular Python objects. The Django ORM does all the heavy work for you whether you need to add a new user, change a password, or delete an old article. This book will explain the basic steps of adding, updating, and deleting data so that you may quickly and confidently manage your database.
What is Django ORM?
Before we get into the “how-to,” let’s be sure we know what we’re talking about. The Django ORM is a great part of the Django web framework that lets your Python code talk to your database.
Structured Query Language (SQL) is the language you would normally use to talk to a database. SQL is a powerful language, but it can get boring. You can use Python to define your data structure (Models) with the ORM. The Django ORM automatically converts your Python commands into the right SQL for your database, whether it’s SQLite, PostgreSQL, or MySQL, once you’ve set up your models.
Django ORM vs SQLAlchemy
You might hear about SQLAlchemy and other tools like it. The biggest difference between Django ORM and SQLAlchemy is how well they work with other software. Django ORM is “batteries-included,” which means that it comes ready to interact with Django’s forms and admin panel. SQLAlchemy is more adaptable and works with a lot of different frameworks, but it needs more manual setup. The built-in ORM is usually the better and simpler alternative for Class 7 students or others who are just starting with Django ORM.
Inserting Data Using Django ORM
Adding new information to your database is called “inserting.” In Django, every row in your database table is represented by a Python object. There are two primary ways to add data.
1. Using the .save() Method
This is the most common way to insert data. You create an instance of your model class and then call the .save() function.
- Step 1: Create the object by assigning values to the fields.
- Step 2: Call the save method to push it to the database.
Example:
If you have a model called Student, you would write:
obj = Student(first_name=”John”, last_name=”Doe”)
obj.save()
2. Using the .objects.create() Method
If you want to do everything in one single line, you can use the .create() method. This is often faster because it saves the object immediately without needing an extra line for .save().
- Benefit: It returns the created object immediately.
- Use case: Best for quick scripts or simple data entry.
Updating Data in the Database using Django ORM
Change in information required the data to be updated, such as a user updating their email address or a price change in an online store.
Individual Updates
To update a specific record, you first need to find it. We usually do this using a unique ID or a specific attribute. Once found, you change the attribute and save it.
- Retrieve the object: Use Student.objects.get(id=1).
- Change the value: obj.first_name = “Jane”.
- Save the change: obj.save().
Bulk Updates with Django ORM Update
Sometimes you want to change many records at once. Instead of looping through every single student and saving them one by one (which is slow), you can use the django orm update functionality.
By using the django orm filter method, you can select a specific group and change them all instantly. For example, if you want to change the “status” of all students in a specific grade to “Promoted,” you can do it in one line of code. This is much more efficient for the database.
Searching and Filtering Data using Django ORM
You can’t update or delete data if you can’t find it. The django orm filter is the tool you will use most often.
- Filter: Returns a list of objects that match your search terms. If no matches are found, it returns an empty list.
- Get: Returns exactly one object. If it finds more than one or zero, it will show an error.
- All: Fetches every single record from the table.
Performance is very important in online apps these days. We won’t go into too much detail today, however advanced devs often use django ORM async to handle these searches without making the rest of the app freeze. This keeps the website speedy even when thousands of individuals are looking for information at the same time.
Deleting Data Safely using Django ORM
You have to be careful when you delete data because it can’t be undone. You can delete one item or a set of things, just like you may update the data.
Deleting a Single Entry
To remove one specific record:
- Find the record: obj = Student.objects.get(id=5).
- Delete it: obj.delete().
Deleting Multiple Entries
If you want to delete old data, you can combine the filter and delete methods. For example, to delete all records where the “active” status is set to “False,” you would filter for those inactive records and then call .delete() on the whole group.
Important Note: When you delete something in Django, it normally does a “cascade delete.” This means that if you delete a “Teacher,” Django might also delete all the “Classes” that are tied to that teacher. Check your links twice!
Summary Table of Commands using Django ORM
If you wish to revise how to use Django ORM quickly, here is a table for you:
| Action | Django ORM Method | Purpose |
| Insert | .save() or .create() | Adds a new row to your table. |
| Update | .update() | Changes existing information for one or many rows. |
| Filter | .filter() | Finds specific data based on conditions. |
| Delete | .delete() | Removes records permanently from the database. |
Why should you use the Django ORM?
The Django ORM cleans up and makes your code easier to read. It keeps hackers from stealing data by protecting your website from “SQL Injection” attacks, which are popular ways they try to do this. Django automatically cleans the data for you because you are writing Python code instead of raw SQL text.
Moreover, using the ORM makes your project “database agnostic.” This means if you start your project using a small SQLite database but later decide to move to a massive PostgreSQL database, you don’t have to rewrite your code. The ORM handles the translation for you.
Django ORM FAQs
- Is Django ORM better than writing SQL?
For most tasks, yes. Django ORM is safer and faster to write. However, for extremely complex reports, some developers still use raw SQL.
- Can I update multiple rows at once?
Yes, you can use the django ORM update function on a filtered list of objects to modify a lot of records at once.
- What happens if I use .get() and the item doesn’t exist?
Django will give you a DoesNotExist error. It’s safer to use the django ORM filter instead if you’re not sure the item is there.
- Does Django ORM support asynchronous coding?
Yes, recent versions of Django have introduced django ORM async support, allowing you to perform database queries without blocking other tasks.
- How do I choose between Django ORM vs SQLAlchemy?
Use the Django ORM if you are making a website with Django. SQLAlchemy is a wonderful choice if you want to make a Python program that isn’t based on Django.
Topics Related To Python
🔹 Python Introduction & Fundamentals |
🔹 Functions & Lambda |
🔹 Python for Machine Learning |
🔹 Python for Web Development |
🔹 Python Automation & Scripting |
🔹 Comparisons & Differences |
🔹 Other / Unclassified Python Topics |
| Asyncio – A Guide |