Search with % in oracle text

Question

How can i retrieve the records which has "80%" "and" keyword using oracle text . Because oracle consider " % , and , or " as the stopwords ... But i want to do the search on "80%" not "80" how to do that ....
below query retrieving both "80" and "80%" records....but i want only "80%"
SELECT ID, AUTHOR, DOCUMENT, PATH, PATH1
FROM DATASTORES_TAB a
WHERE contains ( dummy_col,'{80%}' ) > 0;

Answer 1

Try this...
exec ctx_ddl.drop_preference('my_basic_lexer')
BEGIN
ctx_ddl.create_preference
preference_name => 'my_basic_lexer',
object_name => 'basic_lexer'
ctx_ddl.set_attribute
preference_name => 'my_basic_lexer',
attribute_name => 'printjoins',
attribute_value => '_%'
END;
drop table t1;
create table t1 (text varchar2(80));
insert into t1 values ('My example is 80% complete');
insert into t1 values ('This contains 80 without percent');
insert into t1 values ('This contains 801 without percent');
insert into t1 values ('Na%me1');
insert into t1 values ('Narme1');
CREATE INDEX t1_index ON t1 ( text )
indextype IS ctxsys.context
parameters ( 'lexer my_basic_lexer' );
select text from t1 where contains (text, '80%') > 0;
select text from t1 where contains (text, 'Na%me1') > 0;
select text from t1 where contains (text, '{80%}') > 0;
select text from t1 where contains (text, '{Na%me1}') > 0;
Output:
SQL> select text from t1 where contains (text, '80%') > 0;
TEXT
My example is 80% complete
This contains 80 without percent
This contains 801 without percent
Elapsed: 00:00:00.01
SQL> select text from t1 where contains (text, 'Na%me1') > 0;
TEXT
Na%me1
Narme1
Elapsed: 00:00:00.01
SQL> select text from t1 where contains (text, '{80%}') > 0;
TEXT
My example is 80% complete
Elapsed: 00:00:00.00
SQL> select text from t1 where contains (text, '{Na%me1}') > 0;
TEXT
Na%me1