text: CREATE TABLE especie
  (
    id serial NOT NULL,
    nome character varying(50) NOT NULL,
    CONSTRAINT pk_especie PRIMARY KEY (id ),
    CONSTRAINT un_especie_nome UNIQUE (nome )
  )
  WITH (
    OIDS=FALSE
  );
  
  CREATE TABLE raca
  (
    id serial NOT NULL,
    especie_id integer NOT NULL,
    nome character varying(50) NOT NULL,
    CONSTRAINT pk_raca PRIMARY KEY (id ),
    CONSTRAINT fk_raca_especie FOREIGN KEY (especie_id)
        REFERENCES especie (id) MATCH SIMPLE
        ON UPDATE NO ACTION ON DELETE NO ACTION,
    CONSTRAINT un_raca UNIQUE (especie_id , nome )
  )
  WITH (
    OIDS=FALSE
  );
  
  