Gain insights into developing web applications using Flask, a lightweight and easy-to-learn Python framework. Delve into techniques that make you a sought-after full-stack developer.

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This project-based course is a detailed guide to web application development using the increasingly popular Flask framework.

Flask is known for being simple, lightweight and having a small learning curve. If you've got some experience in Python, picking up Flask will be a breeze. It's got a booming job market and will put you on track to becoming an in-demand full-stack developer. What's not to love?

Flask: Develop Web Applications in Python

# Introduction
Finally, in this chapter, we will learn to handle the data using a database. Up until now, we have been using some data structures like a dictionary, but in a real-world application, this approach is *rarely*, **if ever**, used. We will be using an SQL database and an object relation mapper to manipulate that database inside `Flask`.

>> ### 📌 What is an ORM or object relation mapper?
>> An **ORM** makes writing SQL queries easier for a programmer. It enables us to write queries in an object-oriented language, and then the **ORM** automatically translates it to SQL and retrieves the results in the form of objects!

> ## Introduction to `SQLAlchemy`
> **`SQLAlchemy`** is a library in Python which allows us to manipulate SQL. It provides us with an easy to use `ORM` for SQL databases.

> ## Introduction to `Flask-SQLAlchemy`
> **`Flask-SQLAlchemy`** is a `Flask` specific library that integrates the `SQLAlchemy` support with `Flask` applications. It provides extra helpers for common tasks that make it easier to work with `Flask`.

# How to initiate a database connection 
That's enough about theoretical concepts. Let's dive deep into the programming aspect of databases. Initially, we must first create a database connection. We take the following steps to initiate the database connection:
## Import `SQLAlchemy` 
We will first import the `SQLAlchemy` class from the `flask_sqlalchemy` module in the main application file of our project, i.e., `app.py`. 
```python
from flask_sqlalchemy import SQLAlchemy
```

## Set the `config` variable to the database file
We will have to set a configuration variable in the application so that the application knows where the database file is located. The SQL database we are using is `SQLite`. Therefore, the file name will contain the prefix `sqlite:///` followed by the actual path of the file. However, you can use any other SQL database with SQLAlchemy as well. Now, we will set the config variable `SQLALCHEMY_DATABASE_URI` to point to this file. 
```python
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///example.db'
```

## Initialize the database connection
Now, to complete the initialization, we just have to create an object of the `SQLAlchemy` class. We have to provide our application as a parameter to its constructor. 
```python
database = SQLAlchemy(app)
```

# Complete implementation
Let’s integrate the steps we discussed in the example we covered in the last chapter.

In this lesson, we will be exploring how to create a database connection in your Flask application by using SQLAlchemy.

Before Getting Started

Introduction to Flask

First Flask Application

Build File/Directory Explorer in Flask

Static Templates

Static Files

Dynamic Templates

Form Handling

Database

Operations on Models

Conclusion

Test a MEAN Stack Todo Application with JEST

Build an E-Learning Website Using Flask

Database Connection using SQLAlchemy

Introduction #