DROP DATABASE IF EXISTS db1;
CREATE DATABASE db1;
USE db1;
CREATE TABLE db1.t1 (i INT NOT NULL, UNIQUE INDEX (i));
DELIMITER |
CREATE TRIGGER mytrg BEFORE INSERT ON db1.t1
  FOR EACH ROW BEGIN
    -- This trigger doesn't have to do anything, it just needs to exist.
  END;
|
DELIMITER ;

DROP DATABASE IF EXISTS db2;
CREATE DATABASE db2;
USE db2;
CREATE TABLE db2.t1 (i INT NOT NULL, UNIQUE INDEX (i));
INSERT INTO db2.t1 VALUES (1), (2), (3), (4), (5);