There may be times when you want to limit set size to root words only
from your search query. This is the default in tsql
, Vortex
and the Search Appliance. If using the MM3 API, or if equivalences
have been enabled with keepeqvs
(Vortex/tsql
) or
Synonyms
(Search Appliance), then equivalences can be excluded
for a particular word - while still retaining morpheme processing - by
preceding the word with a tilde (~
). This should be done where
you wish to look for intersections of concepts while holding
abstraction to a minimum, and you do not want any automatic expansion
of those words into word lists. If equivalences are not currently
enabled via keepeqvs
/Synonyms
, then the ~
operator
has the opposite effect: it enables equivalences for that term
only. Thus, it always toggles the pre-set behavior for its word.
Regardless of settings, you can also give explicit equivalences directly in the query, instead of the thesaurus-provided ones, using parentheses; see here.
Where you wish to use morpheme processing on root words only,
restricting concept expansion completely, turn off Equivalence File
access altogether by setting the global APICP flag "keepeqvs
"
off. Where "keepeqvs
" is set to off, the tilde (~
) is
not required (indeed, it would re-enable concept expansion).
Restricting set expansion is useful for proper nouns which you do not
want expanded into abstract concepts (e.g., President Bush
),
technical or legal terminology, or simply any precise discrete search.
Selectively cut off the set expansion by designating a tilde
(~
) preceding the word you are looking for.
Using REX syntax by preceding the word with a forward slash
(/
), can further delimit the pattern you are looking for,
though in a different manner. Note however, that using non-SPM/PPM
pattern matchers such as REX may slow the query, as Metamorph indexes
cannot be used for such terms.
To check this out for yourself, in an application where Metamorph hit
markup has been set up, compare the results of the following queries
(assuming Vortex or tsql
defaults):
Query 1: President Bush
Query 2: ~President ~Bush
Query 3: "President Bush"
Query 4: /President /Bush
Query 5: /\RPresident /\RBush
President Bush
: In the first example you
would get any hit containing an occurrence of the word
"President
" and the word "Bush
", including other
related word forms (suffixes etc.). So you would get a hit like "
President Bush came to tea."; as well as "Bush
attended a conference of corporation presidents." There are
no equivalences added to the "President
" set, or the
"Bush
" set.
~President ~Bush
: In the second example you have
elected to keep the full set size, so you would obtain references to
"President
" and "Bush
" while also allowing for other
abstractions. Since the word "chief
" is associated with
"president
", and the word "jungle
" is associated
with "bush
", you would retrieve a sentence such as, "We
met the chief at his home deep in the Amazon jungle."
"President Bush"
: The third example calls for
"President
" and "Bush
" as a two word phrase by
putting it in quotes, so that it will be treated as one set rather
than as two. It has no equivalences, because the phrase
"President Bush
" has no equivalences known by the Equivalence
File; you could add equivalences to that phrase if you wished by
editing the User Equiv File. While you would retrieve the hit
"President Bush came to tea.", you would exclude the hit
"Bush attended a conference of corporation
presidents." You would get a hit like "We elected a new
president Bush."
/President /Bush
: In the fourth example you
have limited the root word set in a different way. Signalling
REX with the forward slash `/
' means that you will use
REX to accomplish a string search on whatever comes after the
`/
'. Therefore, you can find "Our president's name
is Bush." and "We planted those bushes near the
President's house." This search gets similar yet different
results than Example 1. Look at exactly what is highlighted by the
Metamorph hit markup to see the difference in what was located.
/\RPresident /\RBush
: In the fifth example
there is better reason to use REX syntax, so that you can limit
the set even further by specifying proper nouns only. The designation
`\R
' means to "respect case", and would retrieve the sentence
"President Bush came to tea.", but would rule out
the sentence "Bush attended a conference of corporation
presidents." It would also rule out the hit "We elected
a new president Bush.", and "We planted those
bushes near the President's house."
NOTE: In the previous example, the "respect case" designation
(\R
) must follow a forward slash (/
) which indicates
that REX syntax follows. Remember that words
in a query are not case sensitive unless you so designate,
using REX. (See Chapter on REX syntax.)