A `PRIMARY KEY` is a constraint applied to one or more columns within a table to ensure that each record in the table is uniquely identifiable. It serves as a __unique identifier__ for each row, making it easy to reference and manipulate specific records.



Here's how to define a `PRIMARY KEY` in the structure of a table:

```python
create_table_query = '''
    CREATE TABLE users (
        id INTEGER PRIMARY KEY,
        username TEXT,
        email TEXT
    )
'''
```

The `"id"` column is defined as the `PRIMARY KEY`. This means that each record in the `"users"` table will have a __unique__ `"id"` value, which can be used to __identify__ and access specific records. A `PRIMARY KEY` is crucial for ensuring data integrity and enabling efficient data retrieval.

Which of the following statements best describes a `PRIMARY KEY` in a database?

"Databases in Python" is a hands-on course designed to teach you the fundamentals of working with databases using Python, focusing on the sqlite3 library and SQLAlchemy. You’ll learn how to store, modify, and retrieve data, build efficient queries, and configure databases for your projects. The course covers both SQL basics and the ORM (Object-Relational Mapping) approach, which allows you to interact with databases through Python objects. This course is perfect for beginners looking to deepen their skills in data management, application development, and information handling.

Whether you're new to databases or want to master SQLite, this course will teach you the essentials. You'll learn data management, and how to use SQLite effectively.

CRUD (Create, Read, Update, Delete) are the foundational operations in working with databases. This section is your gateway to mastering these core database functions.

In the "CRUD Operations" section, we will delve into creating, retrieving, updating, and deleting data in a database. You will gain the skills needed to interact with databases effectively, making it an essential tool for your software development journey.

Congratulations on reaching the final section of this course! You've come a long way in your journey to learn and master the content covered.

In this concluding section, we'll summarize key takeaways, reinforce your knowledge, and provide guidance on what you can do next. You've acquired valuable skills and insights, and now it's time to reflect on your achievements and explore how to apply your newfound knowledge effectively.

