Install PostgrSQL-8.4 in Ubuntu

1. sudo apt-get install postgresql postgresql-doc
2. switch user to postgres so as to be able to use PostgreSQL
   
   sudo su postgres
3. Then, we will be able to use PostgreSQL by
   
   psql -d "databasename"
   
   
4. Defind password for user: "postgres" in UNIX system
   
   sudo passwd psotgres
   new password : xxx
   confirm : xxx
   
   
5. Defind password for user: "postgres" in PostgreSQL system
   
   >psql
   >alter user postgres password 'xxx'