Top MCQs on B and B+ Trees with Answers

Question 1

Consider a B+-tree in which the maximum number of keys in a node is 5. What is the minimum number of keys in any non-root node? (GATE CS 2010)

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Question 2

Which one of the following is a key factor for preferring B-trees to binary search trees for indexing database relations?

• Database relations have a large number of records
• Database relations are sorted on the primary key
• B-trees require less memory than binary search trees
• Data transfer form disks is in blocks.

Question 3

B+ trees are preferred to binary trees in databases because (GATE CS 2000)

• Disk capacities are greater than memory capacities
• Disk access is much slower than memory access
• Disk data transfer rates are much less than memory data transfer rates
• Disks are more reliable than memory

Question 4

A B-tree of order 4 is built from scratch by 10 successive insertions. What is the maximum number of node splitting operations that may take place?

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Question 5

The order of a leaf node in a tree B+ ? is the maximum number of (value, data record pointer) pairs it can hold. Given that the block size is 1K bytes, data record pointer is 7 bytes long, the value field is 9 bytes long and a block pointer is 6 bytes long, what is the order of the leaf node?

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Question 6

Consider the following 2-3-4 tree (i.e., B-tree with a minimum degree of two) in which each data item is a letter. The usual alphabetical ordering of letters is used in constructing the tree. What is the result of inserting G in the above tree ?

A) 

B) 

C) 

D) None of the above

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Question 7

A B+ -tree index is to be built on the Name attribute of the relation STUDENT. Assume that all student names are of length 8 bytes, disk block are size 512 bytes, and index pointers are of size 4 bytes. Given this scenario, what would be the best choice of the degree (i.e. the number of pointers per node) of the B+ -tree?

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Question 8

With reference to the B+ tree index of order 1 shown below, the minimum number of nodes (including the root node) that must be fetched in order to satisfy the following query: “Get all records with a search key greater than or equal to 7 and less than 15” is ________

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Question 9

Consider B+ tree in which the search key is 12 bytes long, block size is 1024 bytes, record pointer is 10 bytes long and block pointer is 8 bytes long. The maximum number of keys that can be accommodated in each non-leaf node of the tree is

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Question 10

A B-Tree used as an index for a large database table has four levels including the root node. If a new key is inserted in this index, then the maximum number of nodes that could be newly created in the process are:

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