Python ORM example application
The following tutorial implements a REST API server using the Django ORM. The scenario is that of an e-commerce application where database access is managed using the ORM.
The source for the above application can be found in the python/django
directory of Yugabyte's Using ORMs with YugabyteDB repository.
Prerequisites
This tutorial assumes that you have:
- YugabyteDB up and running. Download and install YugabyteDB by following the steps in Quick start.
- Python 3 or later is installed.
- Django 2.2 or later is installed.
Clone the orm-examples repository
$ git clone https://github.com/YugabyteDB-Samples/orm-examples.git
Set up the database connection
-
Customize the database connection setting according to your environment in the
ybstore/settings.py
file. This file is in theorm-examples/python/django
directory.DATABASES = { 'default': { 'ENGINE': 'django.db.backends.postgresql', 'NAME': 'ysql_django', 'USER': 'yugabyte', 'PASSWORD': '', 'HOST': '127.0.0.1', 'PORT': '5433', } }
-
Generate a Django secret key and paste the generated key in the following line of the
settings.py
file:SECRET_KEY = 'YOUR-SECRET-KEY'
-
Create a database using the YugabyteDB YSQL shell (ysqlsh). From the location of your local YugabyteDB cluster, run the following shell command:
bin/ysqlsh -c "CREATE DATABASE ysql_django"
-
From the
orm-examples/python/django
directory, run the following command to create the migrations and migrate the changes to the database:python3 manage.py makemigrations && python3 manage.py migrate
Start the REST API server
Run the following Python script to start the REST API server at port 8080, or specify a port of your own choice.
python3 manage.py runserver 8080
The REST API server starts and listens for your requests at http://localhost:8080
.
Send requests to the application
Create 2 users.
$ curl --data '{ "firstName" : "John", "lastName" : "Smith", "email" : "jsmith@example.com" }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/users
$ curl --data '{ "firstName" : "Tom", "lastName" : "Stewart", "email" : "tstewart@example.com" }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/users
Create 2 products.
$ curl \
--data '{ "productName": "Notebook", "description": "200 page notebook", "price": 7.50 }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/products
$ curl \
--data '{ "productName": "Pencil", "description": "Mechanical pencil", "price": 2.50 }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/products
Create 2 orders.
$ curl \
--data '{ "userId": "2", "products": [ { "productId": 1, "units": 2 } ] }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/orders
$ curl \
--data '{ "userId": "2", "products": [ { "productId": 1, "units": 2 }, { "productId": 2, "units": 4 } ] }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/orders
Query results
Using the YSQL shell
$ ./bin/ysqlsh
ysqlsh (11.2)
Type "help" for help.
yugabyte=#
yugabyte=# SELECT count(*) FROM users;
count
-------
2
(1 row)
yugabyte=# SELECT count(*) FROM products;
count
-------
2
(1 row)
yugabyte=# SELECT count(*) FROM orders;
count
-------
2
(1 row)
Using the REST API
$ curl http://localhost:8080/users
{
"content": [
{
"userId": 2,
"firstName": "Tom",
"lastName": "Stewart",
"email": "tstewart@example.com"
},
{
"userId": 1,
"firstName": "John",
"lastName": "Smith",
"email": "jsmith@example.com"
}
],
...
}
$ curl http://localhost:8080/products
{
"content": [
{
"productId": 2,
"productName": "Pencil",
"description": "Mechanical pencil",
"price": 2.5
},
{
"productId": 1,
"productName": "Notebook",
"description": "200 page notebook",
"price": 7.5
}
],
...
}
$ curl http://localhost:8080/orders
{
"content": [
{
"orderTime": "2019-05-10T04:26:54.590+0000",
"orderId": "999ae272-f2f4-46a1-bede-5ab765bb27fe",
"user": {
"userId": 2,
"firstName": "Tom",
"lastName": "Stewart",
"email": "tstewart@example.com"
},
"userId": null,
"orderTotal": 25,
"products": []
},
{
"orderTime": "2019-05-10T04:26:48.074+0000",
"orderId": "1598c8d4-1857-4725-a9ab-14deb089ab4e",
"user": {
"userId": 2,
"firstName": "Tom",
"lastName": "Stewart",
"email": "tstewart@example.com"
},
"userId": null,
"orderTotal": 15,
"products": []
}
],
...
}