How to use synonyms on multiple word search ?

Question

We use context with multiword search like this one :
select * from my_table where contains(my_text,'the small building near the river')>0
Now we have specific synonyms in a thesaurus. How do we write the contains clause ?
contains(my_text,'syn(the,thes) and syn(small,thes) and syn(building,thes) and syn(near,thes) and syn (river,thes)')>0 does not fin the synonym for "small building"="house" for instance
contains(my_text,'syn(the small building near the river,thes)')>0 does only for synonyms on the full sentence.
More generally is there an Oracle Document which describes how to use SYN, FUZZY and combine them, since
the reference documentation gives only limited information on this ?
Have a nice day

Answer 1

The thesaurus functionality is not currently built for stuff like this.
if you want to combine fuzzy and thesaurus, I am assuming you want to do fuzzy first, to correct any misspelling,
then thesaurus on the "corrected" spellings? You'd have to do something like:
1. take the query and run ctx_query.explain to break it down and do the fuzzy expansion
2. work through the fuzzy expansion and build a new query string by sticking SYN() around each
expanded word
As for thesaurus expansion and phrase, these are not compatible. Thesaurus expansions use "," and "|", and so
you cannot have a phrase of thesaurus expansions.
I see what you're getting at, but you would need sub phrase detection, phrase equivalence, etc., which is
currently beyond the thesaurus function capability.
You can use themes (ABOUT) on phrases, and it will do something like what you are describing. You might want
to check that out.