Lec-94: Numerical Example on I/O Cost in Indexing | Part-1 | DBMS

Gate Smashers2 minutes read

Understanding indexing through numerical examples is crucial for grasping the concept effectively, such as dividing a hard disk into blocks for efficient data insertion based on block and record size. Without indexing, unordered data entry in blocks results in a linear search with a time complexity of O(N) due to scanning blocks sequentially to find specific records.

Insights

  • Understanding indexing in data storage involves dividing a hard disk into blocks for efficient data insertion based on block and record sizes.
  • Without indexing, searching for records in unordered data on a hard disk requires scanning blocks sequentially, leading to a time complexity of O(N) based on the number of blocks scanned.

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Recent questions

  • What is the importance of understanding indexing?

    Indexing aids in efficient data insertion and retrieval.

  • How does dividing a hard disk into blocks aid in data insertion?

    Dividing a hard disk into blocks allows for organized data storage.

  • How is the number of records per block calculated?

    The number of records per block is based on block size and record size.

  • What is the significance of indexing in data search operations?

    Indexing reduces the time complexity of data search operations.

  • How does unordered data entry impact data search efficiency?

    Unordered data entry necessitates sequential scanning for specific records.

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Summary

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Indexing: Key to Efficient Data Storage

  • Understanding indexing through numerical examples is crucial for grasping the concept effectively.
  • A practical example involving a hard disk with block sizes and record sizes is used to explain the concept.
  • Dividing a hard disk into blocks logically aids in efficient data insertion.
  • The calculation of the number of records that can be inserted in each block is based on the block size and record size.
  • The total number of blocks required to store a given number of records is determined by dividing the total records by the records per block.
  • Unordered data entry in blocks necessitates scanning blocks sequentially to search for specific records.
  • The average time complexity for searching a record from a hard disk without indexing is determined by the number of blocks scanned, resulting in a linear search with a time complexity of O(N).
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