text: -- coding: UTF-8
  
  CREATE TABLE metadata (key VARCHAR(50) PRIMARY KEY, value VARCHAR(50));
  INSERT INTO metadata (key, value) VALUES
      ('version', '0.1'),
      ('author', 'Liu Yuhui'),
      ('description', 'An app to keep a personal dictionary. OoQ');
  
  CREATE TABLE word (
      wid SERIAL PRIMARY KEY, 
      word VARCHAR(80) UNIQUE NOT NULL, 
      ctime TIMESTAMP DEFAULT current_timestamp,
      pronounce_eng VARCHAR(300), 
      pronounce_us VARCHAR(300)
  );
  CREATE TABLE word_definition (
      wid INTEGER REFERENCES word (wid) ON DELETE CASCADE,
      type VARCHAR(20), 
      definition VARCHAR(200)
  );
  CREATE TABLE word_variants(
      wid INTEGER REFERENCES word (wid) ON DELETE CASCADE,
      kind VARCHAR(50) NOT NULL, 
      word VARCHAR(80) NOT NULL
  );
  