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EXPLAIN PLAN   «Prev  Next»

Oracle Explain Plan - Quiz

Each question is worth one point. Select the best answer or answers for each question.
 
1. What is required to view the EXPLAIN output for an SQL query? (Choose all that apply)
Please select all the correct answers.
  A. You must buy an SQL analysis tool.
  B. Create a PLAN table in your schema.
  C. Run the EXPLAIN PLAN statement.
  D. Run a query to view the contents of the PLAN table.

2. Under what conditions will you see a nested loop table access? (Chose all that apply)
Please select all the correct answers.
  A. When specifying a numeric range in a column in the WHERE clause
  B. When performing a non-correlated subquery
  C. When performing a table join
  D. When performing a computation such as AVG or SUM

3. When is it appropriate to have a full-table scan? (Choose all that apply)
Please select all the correct answers.
  A. When you are reading less than one-fourth of the table rows
  B. When you are reading more than two-thirds of the table rows
  C. When the table is accessed with an index
  D. When the table has fewer than 200 rows

4. When does the order of the table name in the FROM clause become important?
Please select the best answer.
  A. When using the cost-based optimizer with a nested loop access
  B. When using the rule-based optimizer with a nested loop access
  C. When performing full-table scans with multi-block reads
  D. When performing index range scans with the rule-based optimizer