Tip: You should rely on natural language queries; they will usually retrieve useful information that Boolean queries can exclude. With relevance ranking at work, you need not be concerned with reducing the number of retrieved records. Consider using Boolean queries only when a precisely restricted search is appropriate.
Note: You can enter query operators in upper- or lower-case. They are capitalized in the following examples only for purposes of clarity.
word1 OR word2Example:
heaven OR hellThis query will retrieve any record that contains an occurrence of at least one of the two words.
Note: By default, OR is used as the default operator; you don't need to enter it explicitly unless a different default operator has been defined.
word1 AND word2Example:
Burke AND HareThis query will retrieve only those records that contain both of the words.
word1 NOT word2Syntax (unary):
media NOT television NOT GordianThe first query will retrieve only records that contain media and are without any occurrences of television.
The second query will retrieve any record that contains no occurrences of Gordian.
New AND York NOT CityThis query will retrieve records that contain both New and York, but do not contain City.
CAUTION: When combining Boolean operators in a query, you should keep in mind the logic imposed on the query by PLWeb Turbo's operator precedence rules. Precedence rules govern the order in which a query's operations are processed; the relative precedence of different operators may cause a query to be processed with logic that is not immediately obvious.
Tip: When combining operators in a query, you can control the order in which operations within the query are processed by using parentheses as delimiters.[Previous Topic] [Contents] [Next Topic]