Mysql Trigger Loop for query result with many rows - mysql

Question

hi i have a database with many tables and foreign keys like this
CREATE TABLE IF NOT EXISTS `articulos` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`nombre` varchar(63) NOT NULL,
`contenido` text NOT NULL,
`normas_id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=138 ;
CREATE TABLE IF NOT EXISTS `aspectosambientales` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`nombre` varchar(63) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=28 ;
CREATE TABLE IF NOT EXISTS `aspectosambientales_articulos` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`aspectosambientales_id` int(11) NOT NULL,
`articulos_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `fk_aspaspectosambientales1` (`aspectosambientales_id`),
KEY `fk_aspee` (`articulos_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 UTO_INCREMENT=225 ;
CREATE TABLE IF NOT EXISTS `empresas` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`razonsocial` varchar(127) DEFAULT NULL,
`nit` varchar(63) DEFAULT NULL,
`direccion` varchar(127) DEFAULT NULL,
`telefono` varchar(15) DEFAULT NULL,
`web` varchar(63) DEFAULT NULL,
`auth_user_id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;
CREATE TABLE IF NOT EXISTS `articulos_empresas` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`empresas_id` int(11) NOT NULL,
`articulo_id` int(11) NOT NULL,
`acciones` text,
`responsable` varchar(255) DEFAULT NULL,
`plazo` date DEFAULT NULL,
`cumplido` tinyint(1) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `fk_normas_empresas_empresas1` (`empresas_id`),
KEY `fk_normas_empresas_normas1` (`normas_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;
and i need to create a trigger to fill the 'articulos_empresas' after insert in 'empresas' for all rows in 'articulos' that match with 'aspectosambientals' that the new 'empresas' selected.
I get all 'articulos' with this query
SELECT articulos_id FROM aspectosambientales_articulos
WHERE aspectosambientales_id = ID
-- ID is the aspectosambientales_id selected when the 'empresas' row is created
-- maybe something like NEW.aspectosambientales_id
but i dont know how create a loop like ' for loop' in trigger for every result in the query
some like this:
CREATE TRIGGER 'filltableae' AFTER INSERT ON 'empresas'
FOR EACH ROW
BEGIN
DECLARE arrayresult = (SELECT articulos_id FROM aspectosambientales_articulos
WHERE aspectosambientales_id = NEW.aspectosambientales_id)
--- here is when i have to do the loop for all the results
--- for ids in arrayresults
--- insert into articulos_empresas ('',NEW.id, ids, '', '' ,'','')
--- endfor
END
thanks!!!

Answer 1

Based on #Razvan answer i left here the code for the trigger, so maybe can help somebody
DROP TRIGGER IF EXISTS AEINST;
DELIMITER //
CREATE TRIGGER AEINST AFTER INSERT ON procesos_aspectos
FOR EACH ROW
BEGIN
DECLARE done INT DEFAULT FALSE;
DECLARE ids INT;
DECLARE cur CURSOR FOR SELECT articulos_id FROM aspectosambientales_articulos WHERE aspectosambientales_id = NEW.aspectosambientales_id;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
OPEN cur;
ins_loop: LOOP
FETCH cur INTO ids;
IF done THEN
LEAVE ins_loop;
END IF;
INSERT INTO articulos_empresas VALUES (null,ids, NEW.empresas_id,null,null,null,null);
END LOOP;
CLOSE cur;
END; //
DELIMITER ;
thanks again!

Answer 2

As far as I know you can iterate through the result of a SELECT query using cursors.
See here : http://dev.mysql.com/doc/refman/5.0/en/cursors.html