Oracle Database 12c: SQL Fundamentals — Question 29

This statement will fail:
create unique bitmap index on employees(department_id,hire_date);
Why?

Answer options

• A. Bitmap indexes cannot be unique.
• B. The two columns are of different data types.
• C. A bitmap index can be on only one column.
• D. There is already a B*Tree index on DEPARTMENT_ID. A

Correct answer:

Explanation

The correct answer is A because bitmap indexes are inherently designed to be non-unique. Option B is incorrect since both columns can be of compatible data types. Option C is also wrong because a bitmap index can include multiple columns. Option D is irrelevant to the uniqueness constraint of the bitmap index.