User Guide

Using Query Expressions 287
Special characters
The search engine handles a number of characters in particular ways as described in
the following table:
A backslash (\) removes special meaning from whatever character follows it. To enter
a literal backslash in a query, use two in succession; for example:
<FREETEXT>("\"Hello\", said Packard.")
"backslash (\\)"
Composing search expressions
The following rules apply to the composition of search expressions.
Precedence rules
Expressions are read from left to right. The AND operator takes precedence over the
OR operator. However, terms enclosed in parentheses are evaluated first. When the
search engine encounters nested parentheses, it starts with the innermost term.
Prefix and infix notation
You use can using prefix notation or infix notation to define search strings that use
any operator other than an evidence operator. As a result, either of the following
expressions is valid:
•
AND (a,b)
This is prefix notation
•
a AND b
This is infix notation
= MATCHES STARTS
>NEARSTEM
>= NEAR/N SUBSTRING
Accrue OR WILDCARD
AND PARAGRAPH WORD
Verity Search Operators
Characters Description
, ( ) [ These characters end a text token.
= > < ! These characters also end a text token. They are terminated by an
associated end character.
’ @ ‘ < { [ ! These characters signify the start of a delimited token. They are
terminated by an associated end character.