DROP TABLE IF EXISTS messages;
DROP TABLE IF EXISTS channels;
DROP TABLE IF EXISTS users;

CREATE TABLE users
(
  login VARCHAR(20) PRIMARY KEY,
  nickname VARCHAR(20) NOT NULL,
  password VARCHAR(40) NOT NULL
);


CREATE TABLE channels
(
  id SERIAL PRIMARY KEY,
  name VARCHAR(20) NOT NULL
);


CREATE TABLE messages
(
  id SERIAL PRIMARY KEY,
  userLogin VARCHAR(20) NOT NULL,
  channelid INT NOT NULL,
  message VARCHAR(256) NOT NULL,
  timestamp TIMESTAMP NOT NULL default CURRENT_TIMESTAMP,
  FOREIGN KEY(userLogin) REFERENCES users(login)
    ON UPDATE CASCADE ON DELETE CASCADE,
  FOREIGN KEY(channelid) REFERENCES channels(id)
    ON UPDATE CASCADE ON DELETE CASCADE
);