Tutorial on disabling and enabling triggers in MySQL [Recommended]

CREATE TABLE `demo_1` (
 `ID` int(11) NOT NULL AUTO_INCREMENT COMMENT 'Primary key',
 `STUNAME` varchar(32) DEFAULT NULL COMMENT 'Name',
 `AGE` tinyint(4) DEFAULT NULL COMMENT 'Age',
 PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8;

CREATE TABLE `demo_2` (
 `ID` int(11) NOT NULL AUTO_INCREMENT COMMENT 'Primary key',
 `STU_ID` int(11) DEFAULT NULL COMMENT 'Student ID',
 `MATH` double DEFAULT NULL COMMENT 'score',
 PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;

DROP TRIGGER IF EXISTS `insertTragger`;
DELIMITER ;;
CREATE TRIGGER `insertTragger` AFTER INSERT ON `demo_1` FOR EACH ROW begin
select ID INTO @v1 from demo_1 order by ID desc limit 1;
Insert into demo_2(STU_ID, MATH) values(@v1, 98.5);
end
;;
DELIMITER ;

DROP TRIGGER IF EXISTS `insertTragger`;
DELIMITER ;;
CREATE TRIGGER `insertTragger` AFTER INSERT ON `demo_1` FOR EACH ROW begin
if @enable_trigger = 1 then
select ID INTO @v1 from demo_1 order by ID desc limit 1;
Insert into demo_2(STU_ID, MATH) values(@v1, 98.5);
end if;
end
;;
DELIMITER ;

SET @enable_trigger = 1;
INSERT INTO demo_1(STUNAME , AGE) VALUES('Xiao Qiang', 17);
After execution, a data entry 2 Xiaoqiang17 is added to the table demo_1
Table demo_2 also adds a data 2 2 98.5

SET @enable_trigger = 0;
INSERT INTO demo_1(STUNAME , AGE) VALUES('Xiao Qiang', 17);
After execution:
After execution, a data entry 2 Xiaoqiang17 is added to the table demo_1