OCA Oracle Database 12c Installation and Administration Exam Guide (Exam 1Z0-062), 2nd Edition

CERTIFICATION OBJECTIVES

9.01   Explain DML and Undo Data Generation

9.02   Monitor and Administer Undo Data

9.03   Describe the Difference Between Undo Data and Redo Data

9.04   Configure Undo Retention

       Two-Minute Drill

Q&A  Self Test

It is time to investigate what actually happens in memory and on disk when one executes a DML statement: how a change to a table generates both redo and undo. The DML commands change data in tables. They will also change data in indexes, but this is automatic and will happen without the programmer’s knowledge. ...