Question
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:
Official answer and solution
- Official answer
- C
- From
- Official GATE 2015 answer key
Solution
Identify the standard database indexing terminology for index-order correspondence.
In database storage systems:
- A clustered index (or clustering index) is an index whose search key specifies an order that is identical or closely aligned with the physical sequential order of data records in the underlying data file.
- An unclustered index (or secondary index) has search keys ordered independently of the physical storage order of the records.
- Dense vs. Sparse index distinguishes whether an index entry exists for every search key value or only for some blocks.
Hence, an index whose ordering corresponds to the file data records is called a clustered index (option C).
Final answer
C
Common trap
Confusing clustered vs unclustered with dense vs sparse indexing.
The answer is the one in the official GATE answer key. The solution is this site's own explanation.
Source
- Paper
- GATE 2015 Computer Science and Information Technology (CS) Session 1
- Question
- 34 of 65, printed as CS Q.24
- Section
- Computer Science and Information Technology
Report an error in this question
GATE questions are the work of the organising institutes. This site is independent and is not affiliated with them.