Further to postgres on Rails in Fedora 18 but OT

[Roger]

Somewhat very OT and more Rails inclined but I'm hoping someone can help.
After reading on Postgres as advised I went to have a look at the Rails 
tables.
Postgres is working, Rails app  "Booking" is up with one table, 
"reservations", which has some string fields and data has been input for 
testing.
as an example, psql Booking_development roger puts me into the:
psql (9.2.4)
Type "help" for help.
Booking_development=>

\l 
shows:---------------------+----------+----------+-------------+-------------+-----------------------
  Booking_development | postgres | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
  Booking_test               | postgres | UTF8     | en_US.UTF-8 | 
en_US.UTF-8 |
  postgres                      | postgres | UTF8     | en_US.UTF-8 | 
en_US.UTF-8 |
  template0                     | postgres | UTF8     | en_US.UTF-8 | 
en_US.UTF-8 | =c/postgres      | postgres=CTc/postgres
  template1                     | postgres | UTF8     | en_US.UTF-8 | 
en_US.UTF-8 | =c/postgres       | postgres=CTc/postgres

Booking_development=> SELECT "registers".* FROM "registers" ORDER BY 
lname shows nothing because it's a database not a table, but I do not 
understand how to get at it's tables'.
Ok! so how do I access the reservations table and how do I view the 
contents of fields so that I can experiment with totaling columns please.

In sqlite, the string tables contain numbers so the rails to_i changes 
them to integer for adding.
How can I do this with postgres please?
Thanks in advance
Roger

The reason I didn't make the numeric fields integer, is because Rails 
likes to have a select system for fields inputting integers and I do not 
want this.
I have been searching on google all day for answers but as usual, 
responses from Rails officianados is curt and  lacks explanation.
Ta
Roger