Friday, February 5, 2016

Differences between B*Tree and Bitmapped Indexes.


B*Tree indexes:

  • Where we need to maintain the sort order of the data, making it easy to look up range data.
  • Required to use multicolumn indexes, we can use the leading edge columns to resolve a query, even if that query doesn't reference all columns of the index.
  • As per its behavior, its automatically stay balanced.
  • Relatively constant performance of any query.
  • Can also specify reverse and unique
  • Recommended for OLTP databases.

Bitmapped indexes:

  • Use them to index columns with that contain a relatively small number of distinct values.
  • Very compact and using lesser space.
  • Designed for query intensive databases.
  • Not good for range scans.
  • Are available only in Enterprise Edition, in relational databases only.

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