What tables and fields are needed in a PostgreSQL database for this messenger?

For a messenger in PostgreSQL, the following tables and fields are usually needed:

1. users — stores information about users:

id SERIAL PRIMARY KEY,
username VARCHAR UNIQUE NOT NULL,
email VARCHAR UNIQUE NOT NULL,
hashed_password TEXT NOT NULL,
created_at TIMESTAMP DEFAULT now()

2. conversations — chats or dialogues:

id SERIAL PRIMARY KEY,
title VARCHAR,
created_at TIMESTAMP DEFAULT now()

3. conversation_members — links users with chats:

id SERIAL PRIMARY KEY,
conversation_id INT REFERENCES conversations(id),
user_id INT REFERENCES users(id),
joined_at TIMESTAMP DEFAULT now()

4. messages — messages in chats:

id SERIAL PRIMARY KEY,
conversation_id INT REFERENCES conversations(id),
sender_id INT REFERENCES users(id),
content TEXT NOT NULL,
sent_at TIMESTAMP DEFAULT now(),
edited_at TIMESTAMP

Additionally, tables for attachments, message statuses, etc., can be added, but these basics provide the core functionality of a messenger.