To tune Oracle SQL, you must understand the query optimizer. The optimizer is built-in software that determines the most efficient method for a statement to access data.

This part contains the following chapters:

• SQL Processing
  This chapter explains how database processes DDL statements to create objects, DML to modify data, and queries to retrieve data.
• Query Optimizer Concepts
  This chapter describes the most important concepts relating to the query optimizer, including its principal components.
• Query Transformations
  This chapter describes the most important optimizer techniques for transforming queries.