Oracle Database Administration I — Question 100

Which three statements are true about indexes and their administration in an Oracle database? (Choose three.)

Answer options

• A. An index can be created as part of a CREATE TABLE statement.
• B. If a query filters on an indexed column, then it will always be used during execution of the query.
• C. A descending index is a type of function-based index.
• D. A DROP INDEX statement always prevents updates to the table during the drop operation.
• E. A UNIQUE and non-unique index can be created on the same table column.
• F. An INVINSIBLE INDEX is not maintained when Data Manipulation Language (DML) is performed on its underlying table.

Correct answer: A, C, E

Explanation

Option A is correct because an index can indeed be defined within the CREATE TABLE statement. Option C is valid as descending indexes are a specific type of function-based index. Option E is true since both UNIQUE and non-unique indexes can be established on the same column. Options B, D, and F are incorrect; B is misleading as an index may not always be used, D is false because the drop operation does not prevent updates, and F is incorrect since an INVISIBLE INDEX is still maintained during DML operations.