MySQL for Persisting Data

MySQL is a relational database management system used to persist and manage structured data in databases composed of related tables.

Backend applications commonly rely on relational databases to persist information beyond the lifetime of an individual process, such as users, orders, products, subscriptions, and application state.

Understanding SQL directly is important even when using an ORM such as Sequelize because it gives you a clear understanding of how your data is structured, queried, related, and ultimately stored by the database.

Learning objectives

In this module, you'll learn how relational databases work and how to manage application data directly using MySQL and SQL.

After completing this module, you will be able to:

• Create and manage relational databases in MySQL.
• Retrieve data from tables using SQL queries.
• Group and aggregate records to produce summarized results.
• Combine related data from multiple tables using joins.
• Write subqueries to perform more complex data retrieval.
• Insert, update, and remove records.
• Design tables and define relationships using primary and foreign keys.
• Create database users and control their access using roles and privileges.