Database Tables(Models)

📁 Creating the `models.py` File

In this video, we will create our models.py file.

First, create a new Python file inside your Todo application and name it models.py.

Models allow SQLAlchemy to understand the structure of the database tables we intend to create. In other words, models define how our data is stored inside the database.

A database model represents a single record (row) inside a database table.

🧠 Understanding the Todo Model

In our application, we will create a table called todos.

Each record in this table will contain the following fields:

id
title
description
priority
complete

The priority field will be stored as an integer, allowing us to represent importance numerically (for example: 1 = High, 2 = Medium, 3 = Low).

📊 Todos Table Example

ID	Title	Description	Priority	Complete
1	Design homepage	Create the main landing page layout	1	No
2	Set up database	Create tables and relationships for the app	1	Yes
3	Implement API	Build FastAPI endpoints for CRUD operations	2	No
4	Frontend integration	Connect Vue.js frontend to the backend	2	No
5	Testing & deployment	Test features and deploy to production	3	No

📥 Importing the Declarative Base

The first thing we need is the Base class created in our database.py file using SQLAlchemy’s declarative base.

We import it into our models.py file:

from database import Base

This tells SQLAlchemy that any class inheriting from Base should be treated as a database table.

🏗️ Creating the Todos Model

Next, we define the Todos model.

This class represents the todos table in the database.

from database import Base

class Todos(Base):
    __tablename__ = "todos"

The __tablename__ attribute specifies the name of the table in the database.

🧩 Defining Table Columns

Now that we have our model class, we can define the columns that make up the table.

Our table will contain:

id
title
description
priority
complete

🔑 Creating the ID Column

The id column will be our primary key, which uniquely identifies each record.

It will:

Be an integer
Serve as the primary key
Be indexed for faster queries

from database import Base
from sqlalchemy import Column, Integer

class Todos(Base):
    __tablename__ = "todos"
    
    id = Column(Integer, primary_key=True, index=True)

primary_key=True ensures uniqueness for each record.
index=True Improves lookup performance.

🧱 Adding the Remaining Columns

To define the remaining fields, we import String and Boolean.

String is used for text-based columns.
Boolean is used to track whether a todo has been completed.

from database import Base
from sqlalchemy import Column, Integer, String, Boolean

Now we define all remaining columns :

from database import Base
from sqlalchemy import Column, Integer, String, Boolean

class Todos(Base):
    __tablename__ = "todos"

    id = Column(Integer, primary_key=True, index=True)
    title = Column(String, nullable=False)
    description = Column(String)
    priority = Column(Integer)
    complete = Column(Boolean, default=False)

✅ Final Result

Our Todos model now correctly maps to a database table with the following structure:

id → Integer, primary key
title → String
description → String
priority → Integer (numeric importance)
complete → Boolean (defaults to False)

🧾 Summary

To recap:

We created a models.py file
Imported SQLAlchemy’s Base and column types
Defined a Todos model representing the todos table
Used appropriate data types for each column
Ensured priority is stored as an integer
Marked id as the primary key and indexed it for performance

📁 Creating the models.py File