text: 
  BEGIN
  
  DECLARE exit handler for sqlexception
    BEGIN
    ROLLBACK;
  END;
  
  DECLARE exit handler for sqlwarning
   BEGIN
   ROLLBACK;
  END;
  
  START TRANSACTION;
  SELECT * FROM `phpsitemodelo`.`usuario` LIMIT 1000;
  alter table usuario modify email varchar(100) unique;
  C;
  END