Nls_language to be set for english stop words to work,10gR2 on Linux

Question

Hi,
When we search a phrase using contains and if the phrase has a stop word in it then the stop word is identified by Oracle depending upon the session language.
When I set the nls_language for the session to AMERICAN, stop word is not being detected and when I set the language to 'ENGLISH', it is being detected.
Is this because the english being refered in the Full Text corresponds to 'ENGLISH' and not 'AMERICAN'.
I guess it should refer to both american and english also.
It would be nice if anyone can clarify this ASAP.
Thanks a lot in advance.

Answer 1

This is what I am trying to do while creating the index,
begin
execute immediate 'drop table text_search';
exception
when others then
null;
end;
create table text_search (content clob, lang varchar2(3) );
insert into text_search values ('Sun rises in the east','eng');
insert into text_search values ('Sun cet evening','fre');
commit;
begin
ctx_ddl.drop_preference('global_lexer');
exception
when others then
null;
end;
begin
ctx_ddl.drop_preference('english_lexer');
exception
when others then
null;
end;
begin
ctx_ddl.drop_preference('french_lexer');
exception
when others then
null;
end;
begin
ctx_ddl.drop_preference('german_lexer');
exception
when others then
null;
end;
begin
ctx_ddl.create_preference('english_lexer','basic_lexer');
ctx_ddl.create_preference('french_lexer','basic_lexer');
ctx_ddl.create_preference('german_lexer','basic_lexer');
ctx_ddl.set_attribute('german_lexer','composite','german');
ctx_ddl.set_attribute('german_lexer','mixed_case','yes');
ctx_ddl.set_attribute('german_lexer','alternate_spelling','german');
end;
begin
ctx_ddl.create_preference('global_lexer', 'multi_lexer');
ctx_ddl.add_sub_lexer('global_lexer','english','english_lexer','eng');
ctx_ddl.add_sub_lexer('global_lexer','french','french_lexer','fre');
ctx_ddl.add_sub_lexer('global_lexer','german','german_lexer','ger');
ctx_ddl.add_sub_lexer('global_lexer','default','english_lexer');
end;
begin
ctx_ddl.drop_preference('mywordlist');
exception
when others then
null;
end;
begin
ctx_ddl.create_preference('mywordlist', 'BASIC_WORDLIST');
ctx_ddl.set_attribute('mywordlist','STEMMER','ENGLISH');
end;
begin
ctx_ddl.drop_stoplist('multistop');
exception
when others then
null;
end;
begin
ctx_ddl.create_stoplist('multistop', 'MULTI_STOPLIST');
ctx_ddl.add_stopword('multistop', 'cet','french');
ctx_ddl.add_stopword('multistop', 'the','english');
ctx_ddl.add_stopword('multistop', 'for','english');
ctx_ddl.add_stopword('multistop', 'all','english');
ctx_ddl.add_stopword('multistop', 'in','english');
end;
begin
execute immediate 'drop index my_text_search_idx';
exception
when others then
null;
end;
CREATE INDEX my_text_search_idx ON text_search(content)
INDEXTYPE IS CTXSYS.CONTEXT
parameters ('datastore ctxsys.direct_datastore filter ctxsys.null_filter lexer global_lexer wordlist mywordlist language column lang stoplist multistop');
while searching:
NLS_LANGUAGE For the session is 'AMERICAN'.
I run the query,
select * from text_search where contains(content,'$"Sun rises in the east"') >0;
gives no result.
I change the session language as below and the query gives the result.
alter session set nls_language = 'english' ;
Same is happening when I tried for different languages.
Please note that we need to maintain a custom stop list containing stop words for multiple languages.