example.flask.crud-app

Building a CRUD application with Flask and SQLAlchemy

Requirements

Please execute the following commands:

$ sudo apt install -y python3-dev python3-pip python3-virtualenv
$ sudo apt install -y git
$ sudo apt install -y sqlite3
$ git clone https://github.com/macagua/example.flask.crud-app.git flask-crud-app
$ cd ./flask-crud-app
$ virtualenv --python /usr/bin/python3 venv
$ source ./venv/bin/activate
$ pip3 install -U pip
$ pip3 install -r requirements.txt

---

Running

Please execute the following command:

$ python3 bookmanager.py

Open at your Web browser the following link http://127.0.0.1:5000/

Display a Book Manager app, like the previous figure.

---

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';

---

License

This project is licensed under the MIT License - see the LICENSE file for details.

---

References

• Building a CRUD application with Flask and SQLAlchemy.
• SQLAlchemy Unified Tutorial.
• Modifying and Querying Data — Flask-SQLAlchemy Documentation.