Well, we should now have a
firm grasp of the basic concepts behind running the EXPLAIN
PLAN to see the access path to data. This module was not intended to make you an expert, and there is always more to learn, especially when you are working with complex SQL queries. The important concepts from this module include the ability to:
- Understand SQL as a declarative language
- Create a PLAN table
- Run the EXPLAIN PLAN utility
- Detect full-table scans with EXPLAIN PLAN
- Use EXPLAIN PLAN to diagnose table joins
- Read non-correlated subqueries
- Detect index range scans
- Analyze complex EXPLAIN PLAN output