How to build a CRUD application using Flask (Python Framework)

How to build a CRUD application using Flask (Python Framework)

Here's a simple example of how to create a CRUD application using Flask and SQLAlchemy (a popular Python ORM library):

    1. First, you'll need to set up a new Flask project and install the required packages (Flask, Flask-SQLAlchemy, and a database driver).

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# create a new directory for your project and navigate to it

mkdir myproject

cd myproject

# create a virtual environment and activate it

python3 -m venv venv

source venv/bin/activate

# install the required packages

pip install flask flask-sqlalchemy

    2. Next, create a new file app.py in your project directory and import the necessary 

       modules:

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from flask import Flask, render_template, request, redirect

from flask_sqlalchemy import SQLAlchemy

    3. Initialize your Flask application and configure the database:

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app = Flask(name)

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///mydatabase.db'

db = SQLAlchemy(app)

    4. Create a model for your database:

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class Person(db.Model):

    id = db.Column(db.Integer, primary_key=True)

    name = db.Column(db.String(100), nullable=False)

    age = db.Column(db.Integer, nullable=False)

    def init(self, name, age):

        self.name = name

        self.age = age

    5. Create a route for the home page that displays a list of people from the database:

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@app.route('/')

def home():

    people = Person.query.all()

    return render_template('home.html', people=people)

    6. Create routes for the create, read, update, and delete operations:

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@app.route('/create', methods=['GET', 'POST'])

def create():

    if request.method == 'POST':

        name = request.form['name']

        age = request.form['age']

        new_person = Person(name, age)

        db.session.add(new_person)

        db.session.commit()

        return redirect('/')

    return render_template('create.html')

@app.route('/update/<int:id>', methods=['GET', 'POST'])

def update(id):

    person = Person.query.get(id)

    if request.method == 'POST':

        person.name = request.form['name']

        person.age = request.form['age']

        db.session.commit()

        return redirect('/')

    return render_template('update.html', person=person)

@app.route('/delete/<int:id>')

def delete(id):

    person = Person.query.get(id)

    db.session.delete(person)

    db.session.commit()

    return redirect('/')

    7. Create the template files for the home page, create page, and update page.

    8. Finally, create the database and run the application:

       if name == 'main':

        db.create_all()

        app.run(debug=True)

This will create the database and start the application in debug mode. You can then visit http://localhost:5000/ in your web browser to see the application in action. Please note that this is just a basic example and there are many additional features and best practices you should consider when building a real-world application, such as form validation, error handling, and user authentication. Also, in production environments, it is a best practice to use a more robust database like PostgreSQL or MySQL instead of SQLite.