The tokenized query, as well as each query alternative generated by spelling suggestion, is expanded by the MDEX Engine based on thesaurus matches. This topic describes the behavior of the thesaurus expansion feature.
Thesaurus expansion replaces each expanded query term with an
OR
of alternatives.
For example, if the thesaurus expands
pentium
to
intel
and
laptop
to
notebook
, then the query
pentium laptop
will be expanded to:
(pentium OR intel) AND (laptop OR notebook)
assuming the match mode is
MatchAll.
The other match modes (with the exception of MatchBoolean) behave analogously.
If there is a multiple-word thesaurus match, then
OR
is used on the query itself to accommodate the
various ways of partitioning the query terms.
For example, if
high speed
expands to
performance
, then the query
high speed laptop
will be expanded to:
(high AND speed AND (laptop OR notebook)) OR (performance AND (laptop OR notebook))
Multiple-word thesaurus matches only apply when the words appear
in exact sequence in the query. The queries
speed high laptop
and
high laptop speed
do not activate the expansion
to performance
.