Search for a command to run...
In this blog you will learn 5 tips to improve your ORM queries in Django
Experienced Full Stack Software Engineer with 4+ Years of experience, proficient in Django and React, with expertise in Python, JavaScript and Typescript, also an author of Dev.Junction Blogs & YouTube Channel, expert in Python/Django, Rest Framework, ReactJS/NextJS and TypeScript, currently based in Pune, India.
No comments yet. Be the first to comment.
TypeScript, a Syntactic sugar on top of JavaScript
Are you tired of tightly coupled code and struggling to keep track of events in your Django application? Look no further! Our new e-book, "Django Signals Demystified: A Step-by-Step Guide to Event-Driven Programming" is here to help you master the po...
Maximizing Performance with select_related and prefetch_related in Django
2022 was not a good year financially because I did so many mistakes knowingly or unknowingly that, eventually, made me lose INR 500K over the course of just 6 months. So here are those mistakes which taught me about freelancing, finance management et...
Improve the user experience and efficiency of your React app with these simple techniques.
Django is a robust framework, it is used by companies like Disqus, Instagram, Pinterest, Bitbucket, etc.
Let's have a quick look at some of the things that can scale your application easily and help you improve performance.
@property to store the dynamically calculated values for a model, instead of storing it in a column. Using property, you do not have to call the model method using ():class User(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
...
@property
def full_name(self):
return f"{first_name} {last_name}"
user = User.objects.first()
print(user.full_name) # This will work perfectly
@cached_property instead of just @property decorator for Model methods to cache the dynamically calculated value in memory. You have to import it first:from django.utils.functional import cached_property
class User(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
...
@cached_property
def full_name(self):
# The returned value will be cached
return f"{first_name} {last_name}"
user = User.objects.first()
print(user.full_name) # This will work perfectly
Q objects for AND, OR & NOT SQL queries:from django.db.models import Q
# For OR conditions
queryset = User.objects.filter(
Q(first_name__startswith='G') | Q(last_name__startswith='S')
)
# For AND conditions
queryset = User.objects.filter(
Q(first_name__startswith='G') & Q(last_name__startswith='S')
)
# For NOT Queries
queryset = User.objects.filter(~Q(first_name='Gaurav'))
Use select_related, prefetch_related for SQL join operations instead of running multiple queries to get data from related tables.
So basically, whenever you try to access the foreign key values from a table to another table, Django will perform those queries smartly in an efficient way.
select_related is used with ForeignKey & OneToOneField field values, on the other hand, prefetch_related is used with ManyToManyField in Django.
There is simple psychology behind these two ORM methods, Retrieve everything at once if you know you will need it.
Use bulk_create, bulk_update for the creation and updation of many rows at once.
When you run an SQL query, it opens a Database connection, and Opening a database connection is an expensive operation. You have to open up network sessions, authenticate, have authorization checked, and so on.
So if you have hundreds/thousands of records to store in Database, do not use for loop with ORM to perform the creation & Delivery operation.
Instead we have bulk operations in Django ORM with bulk_create and bulk_update.
For more such crispy blogs, follow DevJunction, subscribe to our newsletter and get notified.