schema.dbml

Table Users {
  user_id SERIAL [pk]
  username VARCHAR(50) [not null]
  password VARCHAR(100) [not null]
}

Table Messages {
  message_id SERIAL [pk]
  sender_id INTEGER [not null, ref: > Users.user_id]
  receiver_id INTEGER [not null, ref: > Users.user_id]
  message_text TEXT [not null]
  read BOOLEAN [default: false]
  sent_at TIMESTAMP [default: `CURRENT_TIMESTAMP`]
}

Table Channel
(
    chanel_id SERIAL [pk]
    owner_id INTEGER NOT NULL [not null, ref: > Users.user_id]
    chanel_name VARCHAR(50) UNIQUE NOT NULL
);


Table ChannelUsers
(
    chanel_user_id SERIAL [pk]
    chanel_id INTEGER [not null, ref: > Channel.chanel_id]
    user_id INTEGER [not null, ref: > Users.user_id]
);


Table ChannelMessages
(
    chanel_message_id SERIAL [pk]
    chanel_id INTEGER NOT NULL [not null, ref: > Channel.chanel_id]
    message_text TEXT NOT NULL,
    sent_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);