Oracle Database 21c is the engine driving some of the most critical systems on the planet. "DBA Essentials for 21c," equips you with the essential knowledge and skills to confidently manage and optimize your Oracle Database in the cloud. This book breaks down Oracle Database Setup Wizard, Configuration Assistant, and steps for creating and configuring databases. In the first section, you will learn the basics of 21c, understand its Infrastructure, use its advantages, and learn its role in the modern data landscape. As you progress, you will gain knowledge of tools like Setup Wizard and Configuration Assistant to build powerful database structures and optimize performance. Then advanced topics are covered, where you will discover how to secure your data, troubleshoot common issues, and automate tasks for efficiency with practical tips and best practices.