create table demo(text varchar2(2000))

insert into demo values ('my email is john.smith@oracle.com')

create index demoindex on demo(text) indextype is ctxsys.context

select token_text from dr$demoindex$i

select * from demo where contains(text, 'john.smith') > 0

drop index demoindex

exec ctx_ddl.drop_preference('mylexer') 

exec ctx_ddl.create_preference('mylexer', 'BASIC_LEXER') 

exec ctx_ddl.set_attribute('mylexer', 'PRINTJOINS', '@.') 

create index demoindex on demo(text) indextype is ctxsys.context parameters ('lexer mylexer')

select token_text from dr$demoindex$i

select * from demo where contains(text, 'john.smith') > 0

select * from demo where contains(text, 'john.smith@oracle.com') > 0