| (no operator) |
By default (when neither + nor - is specified) the word is optional, but the records that contain it are rated higher. |
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| + |
A leading plus sign indicates that this word must be present in each record that is returned. |
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| - |
A leading minus sign indicates that this word must not be present in any of the records that are returned. Please note that the - operator acts only to exclude records that are otherwise matched by other search terms. Thus, a search that contains only terms preceded by - returns no results. It does not return "all entries except those containing any of the excluded terms." |
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| > < |
These two operators are used to change a word's contribution to the relevance value that is assigned to a record. The > operator increases the contribution and the < operator decreases it. See the example following this list. |
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| ( ) |
Parentheses group words into subexpressions. Parenthesized groups can be nested. |
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| ~ (tilde) |
A leading tilde acts as a negation operator, causing the word's contribution to the record's relevance to be negative. This is useful for marking "noise" words. A record containing such a word is rated lower than others, but is not excluded altogether, as it would be with the - operator. |
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| * |
The asterisk serves as the truncation (or wildcard) operator. Unlike the other operators, it should be appended to the word to be affected. Words match if they begin with the word preceding the * operator. |
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| " |
A phrase that is enclosed within double quote ('"') characters matches only records that contain the phrase literally, as it was typed. |