尝试在插入表之前编写触发器，我还需要检查记录是否存在，然后插入不应该发生。
DELIMITER $$
DROP trigger IF EXISTS `Before_Insert_igm_vessel_details` $$
CREATE TRIGGER `Before_Insert_igm_vessel_details` BEFORE INSERT ON igm_vessel_details
FOR EACH ROW
BEGIN
IF (NOT EXISTS(SELECT * FROM igm_vessel_details WHERE VD_MESSAGE_TYPE = NEW.VD_MESSAGE_TYPE and
VD_CUSTOM_HOUSE_CODE = NEW.VD_CUSTOM_HOUSE_CODE and VD_IGM_NO = NEW.VD_IGM_NO and VD_IGM_DATE = NEW.VD_IGM_DATE and
VD_IMO_CODE_OF_VESSEL = NEW.VD_IMO_CODE_OF_VESSEL and VD_VESSEL_CODE = NEW.VD_VESSEL_CODE and VD_SHIPPING_LINE_CODE = VD_SHIPPING_LINE_CODE and
VD_SHIPPING_AGENT_CODE = NEW.VD_SHIPPING_AGENT_CODE and VD_MASTER_NAME = NEW.VD_MASTER_NAME and VD_PORT_OF_ARRIVAL = NEW.VD_PORT_OF_ARRIVAL and
VD_LAST_PORT_CALLED = NEW.VD_LAST_PORT_CALLED and VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL1 = NEW.VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL1 and
VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL2 = NEW.VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL2 and VD_VESSEL_TYPE = NEW.VD_VESSEL_TYPE and VD_TOTAL_NO_OF_LINES = NEW.VD_TOTAL_NO_OF_LINES
and VD_BRIEF_CARGO_DESCRIPTION = NEW.VD_BRIEF_CARGO_DESCRIPTION and VD_EXPECTED_ARRIVAL_DATETIME = NEW.VD_EXPECTED_ARRIVAL_DATETIME and VD_LIGHT_HOUSE_DUES = NEW.VD_LIGHT_HOUSE_DUES
and VD_SAME_BOTTOM_CARGO = NEW.VD_SAME_BOTTOM_CARGO and VD_SHIP_STORES_DECLARATION = NEW.VD_SHIP_STORES_DECLARATION and VD_CREW_LIST_DECLARATION = NEW.VD_CREW_LIST_DECLARATION and VD_PASSENGER_LIST = NEW.VD_PASSENGER_LIST
and VD_CREW_EFFECT_DECLARATION = NEW.VD_CREW_EFFECT_DECLARATION and VD_MARITIME_DECLARATION = NEW.VD_MARITIME_DECLARATION and VD_TERMINAL_OPERATOR_CODE = NEW.VD_TERMINAL_OPERATOR_CODE)) THEN
INSERT INTO fifo_test.igm_vessel_details (VD_MESSAGE_TYPE, VD_CUSTOM_HOUSE_CODE, VD_IGM_NO, VD_IGM_DATE, VD_IMO_CODE_OF_VESSEL,
VD_VESSEL_CODE,VD_SHIPPING_LINE_CODE,VD_SHIPPING_AGENT_CODE,VD_MASTER_NAME,VD_PORT_OF_ARRIVAL,
VD_LAST_PORT_CALLED,VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL1,VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL2,VD_VESSEL_TYPE,
VD_TOTAL_NO_OF_LINES,VD_BRIEF_CARGO_DESCRIPTION,VD_EXPECTED_ARRIVAL_DATETIME)
VALUES (NEW.VD_MESSAGE_TYPE, NEW.VD_CUSTOM_HOUSE_CODE, NEW.VD_IGM_NO, NEW.VD_IGM_DATE, NEW.VD_IMO_CODE_OF_VESSEL,
NEW.VD_VESSEL_CODE,NEW.VD_SHIPPING_LINE_CODE,NEW.VD_SHIPPING_AGENT_CODE,NEW.VD_MASTER_NAME,NEW.VD_PORT_OF_ARRIVAL,
NEW.VD_LAST_PORT_CALLED,NEW.VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL1,NEW.VD_PORT_CALLED_BEFORE_PORT_OF_ARRIVAL2,NEW.VD_VESSEL_TYPE,
NEW.VD_TOTAL_NO_OF_LINES,NEW.VD_BRIEF_CARGO_DESCRIPTION,NEW.VD_EXPECTED_ARRIVAL_DATETIME);
END IF;
END$$
DELIMITER ;
以上脚本无效。