nivu/example.flask.crud-app

flask-crud-app

Building a CRUD application with Flask and SQLAlchemy

Requeriments

Please execute the following commands:

$ sudo apt-get install git python3-virtualenv python3-pip sqlitebrowser
$ git clone https://github.com/macagua/flask-crud-app.git
$ cd ./flask-crud-app
$ virtualenv --python=/usr/bin/python3 venv
$ source ./venv/bin/activate
$ pip3 install -r requirements.txt

Running

Please execute the following command:

$ python3 bookmanager.py
 * Serving Flask app "bookmanager" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Running on http://0.0.0.0:8087/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 245-060-649
127.0.0.1 - - [04/Jul/2019 14:21:17] "GET / HTTP/1.1" 200 -
127.0.0.1 - - [04/Jul/2019 14:21:18] "GET /favicon.ico HTTP/1.1" 404 -

Open at your Web browser the following link http://127.0.0.1:8087

SQLAlchemy to SQL

db.session.commit():

INSERT INTO book (title) VALUES ('The Hobbie');
INSERT INTO book (title) VALUES ('The Lord of Rings');
INSERT INTO book (title) VALUES ('The Silmarillion');
INSERT INTO book (title) VALUES ('The Children of Húrin');
COMMIT;

UPDATE book
SET title='The Lord of the Rings'
WHERE title = 'The Lord of Rings';
COMMIT;

Book.query.all():

SELECT * FROM book;

Book.query.filter_by(title=oldtitle).first():

SELECT book.title
FROM book
WHERE book.title = 'The Hobbie'
LIMIT 1 OFFSET 0;

db.session.delete(book):

DELETE FROM book
WHERE book.title = 'The Children of Húrin';

Reference

• https://www.codementor.io/garethdwyer/building-a-crud-application-with-flask-and-sqlalchemy-dm3wv7yu2
• https://docs.sqlalchemy.org/en/latest/orm/tutorial.html
• http://flask-sqlalchemy.pocoo.org/2.3/queries/