Querying a text field with an escape character in it.

Question

I want to retrive a the search results from the database with the search string being something like
say "{2.5}"
select cola from tableX where contains(cola, '{{2.5}}', 1)>0)
I tried to parse the string with another escape character - ie i modified the search string to like this
{\{2.5\}}. Doing so i am getting a wrong result. That is it is ignoring the two braces and giving me results that contains only 2.5.
Please give me a solution
Thanks in Advance.
Venkat

Answer 1

You need to define the braces as PRINTJOINS characters, otherwise they are stripped from the term during both indexing and query processing, making "{2.5}" identical to "2.5"
Try this example:
set echo on
drop table x;
create table x (x varchar2(50));
insert into x values ('2.5');
insert into x values ('{2.5}');
exec ctx_ddl.drop_preference('mylex')
exec ctx_ddl.create_preference('mylex', 'basic_lexer')
exec ctx_ddl.set_attribute('mylex', 'printjoins', '{}')
create index xi on x(x) indextype is ctxsys.context
parameters ('lexer mylex');
select x from x where contains (x, '2.5') > 0;
select x from x where contains (x, '\{2.5\}') > 0;