Join selection factor

O'Connell defines join selection factor as "[t]he percentage (or fraction) of records in one file that will be joined with records of another file".[1] This can be calculated when two database tables are to be joined. It is primarily concerned with query optimisation.

References

  1. ↑ O'Connell, S. (2005) Advanced Databases Course Notes, Southampton, University of Southampton, section 5.10


This article is issued from Wikipedia - version of the Saturday, February 20, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.