Database structure for two-step registration flow

Question

I'm trying to design a database for supporting a multi-step registration flow. The registration flow goes like this: the user logs in via OAuth (which creates a session and user), then they're asked to complete the registration by providing a name and username. What is the best way to capture this in the database?

Should I just make a single user table with nullable name and username columns?:

CREATE TABLE users ( id UUID PRIMARY KEY, name TEXT, username TEXT ); CREATE TABLE sessions ( id TEXT PRIMARY KEY, user_id UUID NOT NULL REFERENCES users (id), expires_at TIMESTAMPTZ NOT NULL ); 

Or should I separate the profile information into a separate table like this:

CREATE TABLE users ( id UUID PRIMARY KEY, profile_id UUID ); CREATE TABLE profiles ( id UUID PRIMARY KEY, name TEXT NOT NULL, username TEXT NOT NULL ); ALTER TABLE users ADD FOREIGN KEY (profile_id) REFERENCES profiles (id); CREATE TABLE sessions ( id TEXT PRIMARY KEY, user_id UUID NOT NULL REFERENCES users (id), expires_at TIMESTAMPTZ NOT NULL ); 

I feel that one advantage here is that I can simply check if the profile_id column is null or not to determine if the user has completed the registration process. But I'm not sure if this a good idea.

Any opinions of this? What's the conventional way of going about this?

Answer 1

With a Single Users Table and nullable fields is typically more efficient for simple flows. It minimizes joins and keeps queries straightforward. You can easily check if registration is complete by verifying if name or username is null.

However, separating profiles into its own table provides better normalization and scalability. If you expect profile growth or need more structured data. This also cleanly separate concerns between authentication (OAuth) and user profile details.