Flask SQLite CRUD Application

A simple Flask web application demonstrating basic CRUD (Create, Read, Update, Delete) operations using SQLite3 as the database backend.

Features

• View all users in a table
• Add new users
• Edit existing user information
• Delete users
• Flash messages for user feedback (success/warning)

Requirements

• Python 3.x
• Flask
• SQLite3 (usually included with Python)

Installation

1. Clone or download this project to your local machine.

2. Install dependencies:

   pip install Flask

3. Initialize the database (optional – the app will work without it, but you’ll need a users table):

   Create a file named db_web.db and run the following SQL command to create the users table:

   CREATE TABLE users (
       UID INTEGER PRIMARY KEY AUTOINCREMENT,
       UNAME TEXT NOT NULL,
       CONTACT TEXT NOT NULL
   );

   Alternatively, you can use a Python script to set up the database:

   import sqlite3
   conn = sqlite3.connect('db_web.db')
   conn.execute('''CREATE TABLE users (
                   UID INTEGER PRIMARY KEY AUTOINCREMENT,
                   UNAME TEXT NOT NULL,
                   CONTACT TEXT NOT NULL);''')
   conn.close()

4. Run the application:

   python app.py

5. Open your browser and go to:

   http://127.0.0.1:5000
   

Project Structure

.
├── app.py                 # Main Flask application
├── db_web.db              # SQLite database (created after first use)
├── templates/
│   ├── index.html         # Homepage listing all users
│   ├── add_user.html      # Form to add a new user
│   └── edit_user.html     # Form to edit an existing user
└── README.md

Routes

Route	Method	Description
/ or /index	GET	Display all users
/add_user	GET	Show form to add a new user
/add_user	POST	Insert new user into database
/edit_user/<uid>	GET	Show form to edit user
/edit_user/<uid>	POST	Update user in database
/delete_user/<uid>	GET	Delete user from database

Security Note

• This is a demo application for learning purposes.
• It does not include input validation, CSRF protection, or SQL injection safeguards beyond parameterized queries.
• Do not use in production without proper security enhancements.

License

This project is open-source and available under the MIT License.