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
You might recall that at the beginning of this course, we learned about three **components** of a web application: 
1. **Views** 
2. **Templates** 
3. **Models** 

In previous lessons, we have covered two of these components (**views** and **templates**). In this lesson, we will figure out how to create **models**. Later in the course, we will also get to know how to manipulate these models.


 
# Steps to create a `User` model in a database

Again, let’s get help from the example we have been using. We used a dictionary to store the user’s data.



```python
users = {
    "archie.andrews@email.com": "football4life",
    "veronica.lodge@email.com": "fashiondiva"
}
```
But this is poor application logic. Therefore, to store the user data inside the database, we first need to create models. The models will define the schema for the database table, its properties, and its functionalities. 
## Create a model class for `User`
First, we will create a class for the `User` table. This class will inherit from the model class from SQLAlchemy. 
```python3
class User(db.Model):
```
## Add columns/attributes
Next, we will add the columns for the table. In the example, the users only had two fields: email and password. So we will add them. Each column will be an object of the `Column` subclass of `SQLAlchemy`. 
```python
    email = db.Column(db.String, primary_key=True, unique=True, nullable=False)
    password = db.Column(db.String, nullable=False)
```
In the snippet given above you can observe that we have given some additional parameters to the columns. The **first parameter** of the column defines the data type for the column. Following are the allowed class names:
1. **`Integer`** 
2. **`String(size)`** 
3. **`Text`** 
4. **`DateTime`** 
5. **`Float`** 
6. **`Boolean`**
7. **`PickleType`**
8. **`LargeBinary`**

There are many optional parameters as well; some of the most commonly used ones are given below:
- **`primary_key`**: If set `True`, it will indicate the primary key of the table. 
- **`nullable`**: If set `False`, it will be compulsory to set the value for that column. 
- **`unique`**: If this parameter is set to `True` then all values for this column are checked for uniqueness. 
- **`index`**: Setting it to `True` indicates that this column will be indexed. 
## Creating a table in a database
Now, with a simple command, the model that we just made will be created in the database. 
```python
db.create_all()
```
> 📌 **Important Note:** The `create_all()` command should be called **after** the models are declared. If the models are defined in a separate module, then they should be imported first. Furthermore, during development, if new models are created, then this command **only creates the newly defined models**. 

# Complete implementation
Let's add this implementation to the previously discussed example.

>  📌 **Note:** You will notice that we have not yet removed the dictionary from this example. This is because we have yet to learn how to retrieve and manipulate the data from the **models**.

In this lesson, we will find out how to create models in our Flask application. 

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

Getting Started with Models

Introduction