flask-crud-app

Building a CRUD application with Flask and SQLAlchemy

Requirements

Please execute the following commands:

$ sudo apt install git python3-virtualenv python3-pip
$ sudo apt install git
$ sudo apt install sqlite3
$ 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 --upgrade pip
$ pip3 install -r requirements.txt

Running

Please execute the following command:

$ python3 bookmanager.py
 * Serving Flask app 'bookmanager'
 * Debug mode: on
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.
 * Running on all addresses (0.0.0.0)
 * Running on http://127.0.0.1:8087
 * Running on http://172.23.215.118:8087
Press CTRL+C to quit
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 641-934-958
127.0.0.1 - - [10/Feb/2025 14:10:06] "GET / HTTP/1.1" 200 -

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

SQLAlchemy to SQL

The following code is an example of how SQLAlchemy translates the Python code to SQL code.

db.session.commit()

Insert the following books into the database:

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 the title of the book 'The Lord of Rings' to 'The Lord of the Rings':

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

---

Book.query.all()

Search for all books:

SELECT * FROM book;

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

Search for the book with the title 'The Hobbie':

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

---

db.session.delete(book):

Delete the book with the title 'The Children of Húrin':

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/20/tutorial/index.html#unified-tutorial
• https://flask-sqlalchemy.palletsprojects.com/en/stable/queries/