The rule-based optimizer (RBO) relies on which of the following? (Choose three.)
A. Data dictionary information about the structure of the referenced objects.
B. The syntax of the SQL statements.
C . Statistics gathered by the DBMS_STATS package.
D. Its set of heuristics to determine which plan will work best.
Explanation:
Answer A, B and D: The RBO does not use statistics to determine execution plans; it uses the syntax of the SQL statement, uses dictionary information about the structure of each object referenced in the statement, and applies a set of rules to determine optimal execution plans.
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