How to add explicit column to the already existing user table in postgressql 9.1 database (drupal7)??????????

hi to all....,
it is really nice to work with drupal and postgresql. very comfortable..., but sometimes we face a issue..., we installed user registration password module. asusual it automatically create a table in postgresql.. but the fact is that it create individual table for each field. i just want to integrate all those fields in single table that too in user table..., to where i change the code or include code., whether in files in user folder or in database folder.
can anyone solve my issue??????????