MySQL的经典用法(五)----触发器

Sql代码 
CREATE TABLE `vardata` (   
  `Id` int(11) NOT NULL AUTO_INCREMENT,   
  `name` varchar(255) DEFAULT NULL,   
  `time` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',   
  `data` double(15,5) DEFAULT '-601.00000',   
  PRIMARY KEY (`Id`,`time`),   
  UNIQUE KEY `unique` (`name`,`time`)   
)   
  
CREATE TABLE `vardata_compute` (   
  `Id` int(11) NOT NULL AUTO_INCREMENT,   
  `name` varchar(255) DEFAULT NULL,   
  `time` datetime DEFAULT NULL,   
  `data` double(15,5) DEFAULT NULL,   
  PRIMARY KEY (`Id`)   
)   

CREATE TABLE `vardata` (
  `Id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `time` datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
  `data` double(15,5) DEFAULT '-601.00000',
  PRIMARY KEY (`Id`,`time`),
  UNIQUE KEY `unique` (`name`,`time`)
)

CREATE TABLE `vardata_compute` (
  `Id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `time` datetime DEFAULT NULL,
  `data` double(15,5) DEFAULT NULL,
  PRIMARY KEY (`Id`)
) 
Sql代码 
DROP TRIGGER IF EXISTS trigger_insert_59data;   
CREATE TRIGGER trigger_insert_59data    
AFTER INSERT    
ON vardata    
FOR EACH ROW    
BEGIN  
     DECLARE time_59 DateTime;                 
     SET time_59 = NEW.time-INTERVAL 1 SECOND;    
     IF MINUTE(NEW.time)=0 AND SECOND(NEW.time)=0 THEN  
        INSERT INTO vardata_compute SET name=NEW.name,time=time_59,data=NEW.data;     
     END IF;      
END;   
  
DROP TRIGGER IF EXISTS trigger_delete_59data;   
CREATE TRIGGER trigger_delete_59data    
AFTER DELETE    
ON vardata    
FOR EACH ROW    
BEGIN  
     DECLARE time_59 DateTime;        
     SET time_59 = OLD.time-INTERVAL 1 SECOND;    
     IF MINUTE(OLD.time)=0 AND SECOND(OLD.time)=0 THEN        
        DELETE FROM vardata_compute WHERE time=time_59 AND name=old.name;   
     END IF;      
END;   
  
DROP TRIGGER IF EXISTS trigger_update_59data;   
CREATE TRIGGER trigger_update_59data    
AFTER UPDATE    
ON vardata    
FOR EACH ROW    
BEGIN  
     DECLARE time_59 DateTime;        
     SET time_59 = NEW.time-INTERVAL 1 SECOND;    
     IF MINUTE(NEW.time)=0 AND SECOND(NEW.time)=0 THEN             
        UPDATE vardata_compute SET data=NEW.data WHERE time=time_59 AND name=NEW.name;   
     END IF;      
END;