OCP 1Z0 052 174

174. Which two statements are true regarding B-tree index? (Choose two.)

A.The leaf blocks in the index are doubly linked.

B.The leaf node stores a bitmap for each key value.

C.The rows with NULL value in key columns also have entries in the index.

D.The deletion of a row from the table causes a logical deletion in index leaf block and the space

becomes available for the new leaf entry.

Answer: AD

B bitmap index

C oracle的B-tree索引不保存null值