# B+ Tree Multiple choice Questions and Answers (MCQs)

## Click on any option to know the CORRECT ANSWERS

 Question 1
In a B+ tree, both the internal nodes and the leaves have keys.
 A True B False

Question 1 Explanation:
In a B+ -tree, only the leaves have keys, and these keys are replicated in non-leaf nodes for defining the path for locating individual records.

 Question 2
Which of the following is true?
 A B + tree allows only the rapid random access B B + tree allows only the rapid sequential access C B + tree allows rapid random access as well as rapid sequential access D B + tree allows rapid random access and slower sequential access

Question 2 Explanation:
The B+ -tree being a variation of B-tree allows rapid random access. In a B+ -tree the leaves are linked together, so it also provides rapid sequential access.

 Question 3
A B+ tree can contain a maximum of 7 pointers in a node. What is the minimum number of keys in leaves?
 A 6 B 3 C 4 D 7

Question 3 Explanation:
Maximum number of pointers in a node is 7, i.e. the order of the B+ -tree is 7. In a B+ tree of order n each leaf node contains at most n - 1 key and at least ⌈(n - 1)/2⌉ keys. Therefore, a minimum number of keys each leaf can have = ⌈(7 - 1)/2⌉ = 3.

 Question 4
Which of the following is false?
 A A B+ -tree grows downwards B A B+ -tree is balanced C In a B+ -tree, the sibling pointers allow sequential searching D B+ -tree is shallower than B-tree

Question 4 Explanation:
A B+ -tree always grows upwards. And In a B+tree - i)The path from the root to every leaf node is of the same length, so the tree is balanced. ii) Leaves are linked, so allow sequential searching. iii) An index is built with a single key per block of data rather than with one key per data record, so it is shallower than B-tree.

 Question 5
Statement 1: When a node is split during insertion, the middle key is promoted to the parent as well as retained in right half-node.

Statement 2: When a key is deleted from the leaf, it is also deleted from the non-leaf nodes of the tree.

 A Statement 1 is true but statement 2 is false B Statement 2 is true but statement 1 is false C Both the statements are true D Both the statements are false