To answer this question, we need to understand the structure of a B*Tree index and how leaf nodes are connected.
A B*Tree index is a balanced tree data structure commonly used in database systems. It is designed to provide efficient searching, insertion, and deletion operations. In a B*Tree index, the leaf nodes contain the actual key-value pairs or references to the actual data.
The leaf nodes of a B*Tree index are connected by a doubly linked list. This means that each leaf node has pointers to both its previous and next leaf nodes. The doubly linked list allows for efficient traversal of the leaf nodes in both directions, which is useful for range queries or sequential access.
Option A) Doubly Linked List - This option is correct because the leaf nodes of a B*Tree index are indeed connected by a doubly linked list. This allows for efficient traversal of the leaf nodes in both directions.
Option B) Singly Linked List - This option is incorrect because the leaf nodes of a B*Tree index are connected by a doubly linked list, not a singly linked list.
Option C) Pointers - This option is incorrect because although pointers are used to establish the connections between the leaf nodes, specifically the previous and next leaf nodes, it is more accurate to say that they are connected by a doubly linked list.
Option D) Structures - This option is incorrect because structures are not used to connect the leaf nodes of a B*Tree index. Rather, the connections between the leaf nodes are established using pointers and a doubly linked list.
Therefore, the correct answer is A) Doubly Linked List.