text: CREATE TABLE People (
      id INT PRIMARY KEY,
      name text NOT NULL UNIQUE
  );
  
  CREATE TABLE Pets (
      id INT PRIMARY KEY,
      name text NOT NULL,
      owner int references People(id)
  );
  
  
  
  INSERT INTO People values (1, 'Minsc');
  INSERT INTO Pets values (1, 'Boo');
  INSERT INTO Pets values (2, 'Boo');
  
  SELECT * FROM Pets;
  Select * FROM People;
  
  ALTER TABLE Pets ADD CONSTRAINT constraint_name UNIQUE (name);
  
  