use COPY TO on normalized database

I am working with PostgreSQL 8.2.4.

I need to use the SQL COPY (COPY table FROM file) statement to
populate my database.

I have created a normalized data model (up to 3NF).  Is it possible to
use COPY TO on a particular table (that is linked to other tables
using foreign keys) whilst keeping the foreign keys and other tables
updated?

(Also, will de-normalizing the model to 2NF or 1NF help?)

Thank you.