Advanced Operators


Two advanced classes of Verity operators are not used with modifiers.

The score operators (YESNO, PRODUCT, SUM, and COMPLEMENT) affect how the search engine calculates scores for retrieved documents. When a score operator is used, the search engine first calculates a separate score for each search element found in a document, and then performs a mathematical operation on the individual element scores to arrive at the final score for each document.

The natural language operators (FREETEXT and LIKE) enable you to specify search criteria using natural language syntax. The search engine uses natural language analysis to translate the query text into Verity query language expression for evaluating and scoring documents.

The following table briefly describes each advanced operator. For examples and more detailed descriptions, see Chapter 5, "Advanced Query Language."

Operator Name
Description
COMPLEMENT
Score operator. Calculates scores for documents matching a query by taking the complement (subtracting from 1) of the scores for the query's search elements.
FREETEXT
Natural language operator. Interprets text using the free text query parser, and scores documents using the resulting query expression. All retrieved documents are relevance-ranked. For information about the free text query parser, see Appendix A.
LIKE
Searches for other documents that are like the sample one or more documents or text passages you provide. The search engine analyzes the provided text to find the most important terms to use for the search. Retrieved documents are relevance-ranked.
PRODUCT
Score operator. Calculates scores for documents matching a query by multiplying the scores for the query's search elements together.
SUM
Score operator. Calculates scores for documents matching a query by adding together the scores for the query's search elements. The maximum sum is always 1.
YESNO
Score operator. Enables you to limit a search to only those documents matching a query, without the score of that query affecting the final scores of the documents.




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