Trigger´s

create trigger checarTorero before insert on corrida_torero for each row
begin
if (select count(idTorero) from corrida_torero where idTorero=new.idTorero and idCorrida=new.idCorrida)<4 then
insert into corrida_torero(idCorrida,idTorero) values (new.idCorrida,new.idTorero);
end if;
end;

create trigger checarToro before insert on corrida_toro for each row
begin
if(select vivo from toro where idToro=new.idToro)>0 then
insert into corrida_toro values(0,new.idCorridas,new.idToro,new.numeroOrden);
end if;
end;