GATE || DBMS || File Organizations || Pyq ( 2010 to 2025 )

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Question 1

An index is clustered, if
[GATE 2013 || MCQ || 1-mark]

It is on a set of fields that form a candidate key.
It is on a set of fields that include the primary key.
The data records of the file are organized in the same order as the data entries of the index.
The data records of the file are organized not in the same order as the data entries of the index.

Question 2

A file is organized so that the ordering of data records is the same as or close to the ordering of data entries in some index. Then that index is called
[GATE 2015 || SET-1 MCQ || 1-mark ]

Dense
Sparse
Clustered
Unclustered

Question 3

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 ___________

[GATE 2015|| SET-2 NAT || 1-mark]

Question 4

Consider a B+ tree in which the search key is 12 bytes long, block size is 1024 bytes, recorder pointer is 10 bytes long and the block pointer is 8 bytes long. The maximum number of keys that can be accommodated in each non-leaf node of the tree is ______.
[GATE 2015|| SET-3 NAT || 2-mark]

Question 5

B+ Trees are considered BALANCED because ......
[GATE 2016|| SET-2 MCQ || 1-mark]

The lengths of the paths from the root to all leaf nodes are all equal.
The lengths of the paths from the root to all leaf nodes differ from each other by at most 1.
The number of children of any two non-leaf sibling nodes differ by at most 1.
The number of records in any two leaf nodes differ by at most 1.

Question 6

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 ______. [GATE 2017 || SET-2 NAT|| 2-mark]

Question 7

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?
[GATE 2019 MCQ || 1-mark ]

Each leaf node has a pointer to the next leaf node
Non-leaf nodes have pointers to data records
B⁺ tree is a height-balanced tree
Key values in each node are kept in sorted order

Question 8

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 ______? [GATE 2020 || NAT || 2-mark]

Question 9

A data file consisting of 1,50,000 student-records is stored on a hard disk with block size of 4096 bytes. The data file is sorted on the primary key RollNo. The size of a record pointer for this disk is 7 bytes. Each student-record has a candidate key attribute called ANum of size 12 bytes. Suppose an index file with records consisting of two fields, ANum value and the record pointer to the corresponding student record, is built and stored on the same disk. Assume that the records of data file and index file are not split across disk blocks. The number of blocks in the index file is ______ .
[GATE 2021|| SET-2 NAT || 1-mark]

Question 10

Consider a database of fixed-length records, stored as an ordered file. The database has 25,000 records, with each record being 100 bytes, of which the primary key occupies 15 bytes. The data file is block-aligned in that each data record is fully contained within a block. The database is indexed by a primary index file, which is also stored as a block-aligned ordered file. The figure below depicts this indexing scheme.

Suppose the block size of the file system is 1024 bytes, and a pointer to a block occupies 5 bytes. The system uses binary search on the index file to search for a record with a given key. You may assume that a binary search on an index file of b blocks takes ⌈log_⁡2b⌉ block accesses in the worst case.
Given a key, the number of block accesses required to identify the block in the data file that may contain a record with the key, in the worst case, is _____
[GATE 2023|| NAT|| 2-mark]

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DBMS

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