>I agree. The other approach I thought is to enter a "dummy" record with blank entry in the primary table and "hide" it from the user. But maybe I will learn to live (code) with NULLs instead of empty entries.

There're three cases where I find NULLs useful
- Dates
- FK
- The columns where it's important to know difference between "empty" and "unknown" values

>Speaking about triggers. Do I understand correctly that specifying foreign key constraint with cascade option is pretty much the same as used to be done with triggers to update foreign keys?

Yes, FK used to be implemented in SQL Server with triggers up to SQL 2000.