Can you give an example of a table with normalized data?

A normalized table in a database is organized to minimize redundancy and ensure data integrity. For example, a "Users" table may contain unique records with fields:

user_id	username	email	created_at
1	ivan	ivan@mail.com	2024-01-10 12:00:00
2	maria	maria@mail.com	2024-02-15 09:30:00

Here:

• user_id is the primary key, a unique identifier.
• username and email are unique or have constraints to avoid duplication.
• There are no repeating or computed data.

In Python, such a table can be represented using a list of dictionaries or a pandas DataFrame:

import pandas as pd

data = [
    {'user_id': 1, 'username': 'ivan', 'email': 'ivan@mail.com', 'created_at': '2024-01-10 12:00:00'},
    {'user_id': 2, 'username': 'maria', 'email': 'maria@mail.com', 'created_at': '2024-02-15 09:30:00'}
]

df = pd.DataFrame(data)
print(df)

This approach ensures a clean data structure without redundancy and facilitates its maintenance and updating.