Ivan Yu

Posted on Apr 20, 2024 • Originally published at ivanyu2021.hashnode.dev

Using Django ORM only without web server

#django #sqlite #python #orm

Django is a great framework, but sometimes you just want to use its ORM without web server function. This blog will introduce how to do it.

1. Step

1.1. Setup environment

Create a virtual environment named ormOnlyEnv and then activate it

python -m venv ormOnlyEnv
ormOnlyEnv\Scripts\activate

Copy the requirement.txt to the same directory as the folder ormOnlyEnv and install it using below command.

pip install -r requirements.txt

Copy manage.py and settings.py to the directory and create directory db. Your project structure should look like as below:

1.2. Create Model class

Create models.py under directory db. Place your own model (data stored to db) in models.py. We use the class Person as an example.

models.py

from django.db import models
from django.utils import timezone

## Create your models here.
class Person(models.Model):

    name = models.CharField(
        max_length=50,
        blank=False
    )
    age = models.IntegerField()
    birth_date = models.DateTimeField(
        blank=False
    )

1.3. Generate database and table

For simplicity, in this example, we use sqlite.

Check if there is any migration script generated and output

python manage.py showmigrations db

db
 (no migrations) --> No script is generated

Generate script and output

python manage.py makemigrations db

Migrations for 'db':
  db\migrations\0001_initial.py
    - Create model Person

Generate table in database and output

python manage.py migrate

Migrations for 'db':
  db\migrations\0001_initial.py
    - Create model Person

1.3.1. Remark

If you have update models.py, remember to run following commands again to synchronize database.

python manage.py makemigrations db
python manage.py migrate

2. Create your own script

Here is the most IMPORTANT point, place the following code at the TOP in the script file to initialize Django ORM in the beginning.

import os
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')
import django
django.setup()

Save the data to db by calling the model class

import datetime
from db.models import Person

print("Project started!!")
person = Person()
person.name = 'John Doe'
person.age = 30
person.birth_date = datetime.datetime(1963, 2, 5)
person.save()
print("Saved!!")

Whole file main.py

##############################
## Django specific settings (Please this BEFORE import model class)
##############################
import django
import os
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')
django.setup()
##############################

import datetime
from db.models import Person

print("Project started!!")
person = Person()
person.name = 'John Doe'
person.age = 30
person.birth_date = datetime.datetime(1963, 2, 5)
person.save()
print("Saved!!")

Run the files and you can see the record is saved to db

python main.py

Project started!!
Saved!!

3. Git repo

https://github.com/ivanyu199012/16-DjangoUsedOrmOnly/

4. Reason I wrote this blog

Recently, I needed to build a python script to save some records to database. I considered manually creating tables and coding sql insert command, but this would cost a lot of times.

I remembered that in the past, I used Django ORM only without the web server to save records to database, so I decided to use it.

I forgot how to do it, so I spent some time to test and refresh my memory and finally I succeed it. This blog is wrote so that in the future, if I forgot how to do it, I can check this blog and hope it can also help the others.

Thanks for reading.😀

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