Flask SQLAlchemy database file is not visible from explorer

Question

Making a database connection using SQLAlchemy and sqlite3 database. my expected behaviour was the engine will make a database file in my directory folder. However the engine didn't create a database file, yet my app connected to a database with no file.

here's the App Factory file:

from flask import Flask
from .config import SECRET_KEY
from .extensions import db
from .blueprints.user import main


def create_app():
    app = Flask(__name__)
    app.config["SECRET_KEY"] = SECRET_KEY
    app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:////database.db"

    db.init_app(app)

    app.register_blueprint(main)

    @app.route('/test')
    def test():
        return 'bruh'
    
    with app.app_context():
        from .models.users import Users
        db.create_all()
    
    return app

app/models/users.py

from ..extensions import db

class Users(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    nama_pembeli = db.Column(db.String, nullable=False)
    email = db.Column(db.String)

again there aren't a database file in my app directory, but when i checked into the Flask shell, the table's are there. i can even insert data into it.

Python 3.11.2 (tags/v3.11.2:878ead1, Feb  7 2023, 16:38:35) [MSC v.1934 64 bit (AMD64)] on win32
App: app.app
Instance: B:\code\instance
>>> Users
<class 'app.app.models.users.Users'>
>>> Users.query.all()
[<Users 1>, <Users 2>]

there are Instance: B:\code\instance in the shell but the directory is not there. is there something wrong with the code or is this a bug?

Answer 1

Based on this issue on Flask-SQLAlchemy I figured out that SQLAlchemy created the database file based on flask app.instance_path variable. So what I have to do was change the variable since it was set outside the project directory.

from flask import Flask
from .config import SECRET_KEY
from .extensions import db
from .blueprints.users import main
import os


def create_app():
    abs_instance_path = os.path.abspath(os.path.join(os.path.dirname( __file__ ), '..', 'instance')) #<--- this will be the instance directory
    app = Flask(__name__, instance_path=abs_instance_path)
    app.config["SECRET_KEY"] = SECRET_KEY
    app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///database.db"

    db.init_app(app)

    app.register_blueprint(main)

    @app.route('/test')
    def test():
        return 'bruh'
    
    with app.app_context():
        from .models.users import Users
        db.create_all()
    
    return app

note that flask only accept absolute path as an argument for app.instance_path