Multiple choice

For which constraints are indexes created when the constraint is added?

  1. Check

  2. Unique

  3. Not null

  4. Primary key

  5. Foreign key
Reveal answer Fill a bubble to check yourself
B,D Correct answer
Explanation

Oracle automatically creates indexes to enforce UNIQUE and PRIMARY KEY constraints. These indexes support the constraint's requirement that values be distinct across rows (or non-null and distinct for PK). CHECK, NOT NULL, and FOREIGN KEY constraints do not automatically create indexes - though you can and often should manually create indexes on foreign key columns for join performance.

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