CREATE TABLE `users` (
  userid VARCHAR(30) NOT NULL UNIQUE,
  passwd VARCHAR(80) NOT NULL,
  uid INTEGER UNIQUE,
  gid INTEGER,
  homedir VARCHAR(255),
  shell VARCHAR(255), 
  last_accessed DATETIME
);
CREATE TABLE `groups` (
  groupname VARCHAR(30) NOT NULL UNIQUE,
  gid INTEGER NOT NULL,
  members VARCHAR(255)
);