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Boolean searches in Primo don't work as expected

  • Product: Primo
  • Product Version: All versions
  • Relevant for Installation Type: All types

 

Symptom:

 

When comparing search results with Boolean operators the numbers don't add up.

For example:

  • Searching for A returns X records
  • Searching for B returns Y records
  • Searching for A AND B returns a number of records greater than  X or Y ( the greater number)

 

Example:

  • Searching for 'documentary' returns 21,473 records
  • Searching for 'film' returns 477,172 records
  • Searching for 'documentary film' returns 24,102 records
  • Searching for 'documentary AND film' returns 21,300 records

Explanation:

 

Primo's search engine has a sophisticated algorithm which expends and alters queries so that the results returned will be relevant to the search.

Such changes relate to searching for:

  • authors
  • synonyms
  • common misspellings
  • Phrase searching
  • Searching in full text of PCI records
  • Etc.

 

The search engine algorithm builds a series of Boolean searches which increases the relevance of the results, as opposed to an SQL search, for instance, which works in a direct manner on the data.

This is important in particular for searches in PCI where, due to its sheer size, a direct search (as SQL) would return an extremely large amount of records, all meeting the search query but  many of them may have low relevance to the end user.

 

Conclusion:

 

The results of different searches aren't necessarily comparable in a linear relation.

 

 


  • Article last edited: 18-Jan-2017
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