Which one of the following statements is NOT correct about the B+ tree data structure used for creating an index of a relational database table?

Q. Which one of the following statements is NOT correct about the B+ tree data structure used for creating an index of a relational database table?

(A) B+ Tree is a height-balanced tree

(B) Non-leaf nodes have pointers to data records

(C) Key values in each node are kept in sorted order

(D) Each leaf node has a pointer to the next leaf node

Ans: Non-leaf nodes have pointers to data records

Solution:

B+ tree is height balance search tree, where key values in each node are kept in sorted order.

All leaf nodes are at same level and connected to next leaf node.

Each non-leaf (i.e., internal) node is of the form:

<P1, K1, P2, K2, ….., Pc-1, Kc-1, Pc>

where c <= a and each Pi is a tree pointer (i.e points to another node of the tree) and, each Ki is a key value. That means each non-leaf (i.e., internal) nodes has only block (i.e., node or tree pointers) and keys. These internal (i.e., non-leaf) node do not contain data record pointers. So, option (B) is not correct.