The
text search engine allows queries to be formed from arbitrary Boolean
expressions containing the keywords AND, OR, and NOT,
and grouped with parentheses. For example:
- information
retrieval
-
finds
documents containing "information" or "retrieval"
- information
or retrieval
-
same
as above
- information
and retrieval
-
finds
documents containing both "information" and
"retrieval"
- information
not retrieval
-
finds
documents containing "information" but not "retrieval"
- (information
not retrieval) and WAIS
-
finds
documents containing "WAIS", plus "information" but
not "retrieval"
- web*
finds
documents containing words starting with "web"
