Several newbyish questions about Rails


I am creating a Rails application and I've run into a couple of snags. Answers to the following questions would be appreciated.

Couple of things to note: I am using a legacy database where all of the tables have an integer primary key called "id."

The application has to coexist with a Java/Hibernate application. The ID for all tables is generated using a Hibernate sequence number. The same sequence is used for all tables.

I am using Postgres 8.2 and 8.3 (depending on my environment)

My questions:

- what is the best way to generate an id for a new object? I want to avoid risks of collision between what the Java app does and what the Ruby ap does.

- when creating a new object, the id is never stored. In my current form, I force the id to be set manually (until I can solve the previous question). Yet, when the data is stored, I get an error from my database saying the id is null. When I look at the code used to store, the ID does not appear. Why not and how do I fix that?

- I have a few fields that set the modification date, and the status (one modified, one for deleted). The database does not set the modification date automatically. What is the preferred way to updated it? Similar question for the modified field.

- For the delete field, I want to set the "delete" flag to TRUE instead of physically deleting the object. What is the best way to do this?

- Finally, I am working with one object for now but I will need to do something similar for five or six other objects. How can I scaffold all of the above so that I have as little code to retype as possible?