I have to create logic for generation unique number identifier for records in database. id, generated in database is a separate column.

At this moment, when user calls "create record" action, I save new record, get its database id, generate record number using this id, then put it to the edit form. Using this way means that all entity fields should be nullable to save record to database.

I don't like this way. I know that should be better way.

Is there a better practice to generate unique number identifier? What is possibility of generating non-unique random numbers?

Thank you