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Answers to practice exam questions

A1: Answer: D.

A2: Answer: D. The other definitions are incorrect. REAL data consists of single-precision floating-point numbers, which can be less than, equal to, or greater than 21. DOUBLE data consists of double-precision floating-point numbers. SMALLINT data consists of small integers, but they need not be less than 22.

A3: Answer: B and D. The statements in the other options are false. Option A is false because no user-defined settings control how DB2 treats null values. Option C is false because a null value is not equivalent to a blank. Option E is false because a null value is not equivalent to a zero value.

A4: Answer: A. The statements in the other options are true. Option A is false because using an index might improve performance, but in some cases a scan of the entire table actually results in better performance than when an index is used.

A5: Answer: C. The statements in the other options are true. Option C is false because many users of tables are unaware of the presence or absence of particular indexes on those tables.

A6: Answer: D. The statements in options A, B, and C do explain the purpose of an index.

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