GATE CSE concept:b-trees PYQs & Answers

Questions 1–7 of 7. Imported answers require independent review unless marked reviewed.

An index in a DBMS is said to be dense if an index entry appears for every search-key value in the indexed file. Otherwise it is called a sparse index. Consider the following two statements.

S1: A hash index must be a dense index

S2: A

tree index can be a sparse index

Which one of the following options is correct?

Your answerChoose one option.

Both S1 and S2 are true

Both S1 and S2 are false

S1 is true and S2 is false

S1 is false and S2 is true

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Consider the following

tree with 5 nodes, in which a node can store at most 3 key values. The value 23 is now inserted in the

tree. Which of the following option(s) is/are CORRECT?

Tree diagram: root keys 6, 12, 19; four leaf nodes contain, respectively, 1, 4, 3; 7, 9, 10; 13, 15, 17; and 20, 21, 22.

Diagram for Computer Science and Information Technology question 21

Your answerSelect all correct options. You can choose more than one.

None of the nodes will split.

At least one node will split and redistribute.

The total number of nodes will remain same.

The height of the tree will increase.

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In a B⁺- tree where each node can hold at most four key values, a root to leaf path consists of the following nodes:

A = (49, 77, 83, -), B = (7, 19, 33, 44), C = (20*, 22*, 25*, 26*)

The *-marked keys signify that these are data entries in a leaf.

Assume that a pointer between keys

and

points to a subtree containing keys in

, and that when a leaf is created, the smallest key in it is copied up into its parent.

A record with key value 23 is inserted into the B⁺- tree.

The smallest key value in the parent of the leaf that contains 25* is __________. (Answer in integer)

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In a B+ tree, the requirement of at least half-full (50%) node occupancy is relaxed for which one of the following cases?

Your answerChoose one option.

Only the root node

All leaf nodes

All internal nodes

Only the leftmost leaf node

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Consider a database implemented using B+ tree for file indexing and installed on a disk drive with block size of 4 KB. The size of search key is 12 bytes and the size of tree/disk pointer is 8 bytes. Assume that the database has one million records. Also assume that no node of the B+ tree and no records are present initially in main memory. Consider that each record fits into one disk block. The minimum number of disk accesses required to retrieve any record in the database is ______.

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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?

Your answerChoose one option.

B+ Tree is a height-balanced tree

Non-leaf nodes have pointers to data records

Key values in each node are kept in sorted order

Each leaf node has a pointer to the next leaf node

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In a B+ tree, if the search-key value is 8 bytes long, the block size is 512 bytes and the block pointer size is 2 bytes, then the maximum order of the B+ tree is __________.

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GATE CSE concept:b-trees PYQs

How to practice concept:b-trees

Question 46

Question 21

Question 57

Question 21

Question 54

Question 14

Question 49