Project: YugabyteDB (App Definition and Development / Database)
File: ysql-sqlalchemy.md

title: Python ORM example application that uses SQLAlchemy and YSQL headerTitle: Python ORM example application linkTitle: Python description: Python ORM example application that uses SQLAlchemy and YSQL. menu: v2.18: identifier: python-sqlalchemy parent: orm-tutorials weight: 670 type: docs <ul class="nav nav-tabs-alt nav-tabs-yb"> <li > <a href="../ysql-sqlalchemy/" class="nav-link active"> <i class="icon-postgres" aria-hidden="true"></i> SQLAlchemy ORM </a> </li> <li> <a href="../ysql-django/" class="nav-link"> <i class="icon-postgres" aria-hidden="true"></i> Django ORM </a> </li> </ul> This SQLAlchemy ORM example, running on Python, implements a basic REST API server for an e-commerce application scenario. Database access in this application is managed through . The source for this application can be found in the of Yugabyte's GitHub repository. This tutorial assumes that you have: YugabyteDB up and running. Download and install YugabyteDB by following the steps in . Python 3 is installed the Python packages (dependencies) : , and installed: To install these three packages, run the following command: ```sh $ pip3 install psycopg2-binary sqlalchemy jsonpickle ``` Clone the Yugabyte by running the following command. ```sh $ git clone https://github.com/YugabyteDB-Samples/orm-examples.git ``` Update the database settings in the `src/config.py` file to match the following. If YSQL authentication is enabled, add the password (default for the `yugabyte` user is `yugabyte`). ```python import logging listen_port = 8080 db_user = 'yugabyte' db_password = 'yugabyte' database = 'ysql_sqlalchemy' schema = 'ysql_sqlalchemy' db_host = 'localhost' db_port = 5433 logging.basicConfig( level=logging.INFO, format="%(asctime)s:%(levelname)s:%(message)s" ) ``` Run the following Python script to start the server. ```sh python3 ./src/rest-service.py ``` The REST API server will start and listen for your requests at `http://localhost:8080`. Create 2 users. ```sh $ curl --data '{ "firstName" : "John", "lastName" : "Smith", "email" : "jsmith@example.com" }' \ -v -X POST -H 'Content-Type:application/json' http://localhost:8080/users ``` ```sh $ 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. ```sh $ curl \ --data '{ "productName": "Notebook", "description": "200 page notebook", "price": 7.50 }' \ -v -X POST -H 'Content-Type:application/json' http://localhost:8080/products ``` ```sh $ 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. ```sh $ curl \ --data '{ "userId": "2", "products": [ { "productId": 1, "units": 2 } ] }' \ -v -X POST -H 'Content-Type:application/json' http://localhost:8080/orders ``` ```sh $ 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 ``` ```sh $ ./bin/ysqlsh ``` ```output ysqlsh (11.2) Type "help" for help. yugabyte=# ``` ```plpgsql yugabyte=# SELECT count(*) FROM users; ``` ```output count 2 (1 row) ``` ```plpgsql yugabyte=# SELECT count(*) FROM products; ``` ```output count 2 (1 row) ``` ```plpgsql yugabyte=# SELECT count(*) FROM orders; ``` ```output count 2 (1 row) ``` ```sh $ curl http://localhost:8080/users ``` ```output.json { "content": [ { "userId": 2, "firstName": "Tom", "lastName": "Stewart", "email": "tstewart@example.com" }, { "userId": 1, "firstName": "John", "lastName": "Smith", "email": "jsmith@example.com" } ], ... } ``` ```sh $ curl http://localhost:8080/products ``` ```output.json { "content": [ { "productId": 2, "productName": "Pencil", "description": "Mechanical pencil", "price": 2.5 }, { "productId": 1, "productName": "Notebook", "description": "200 page notebook", "price": 7.5 } ], ... } ``` ```sh $ curl http://localhost:8080/orders ``` ```output.json { "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": [] } ], ... } ```