Setting up MySQL trigger syntax correctly and carefully - mysql

Question

I've been doing a lot of new learning about MySQL and triggers. I think I understand the concept and I realise there are a LOT of possible dangers in using them. However I believe the limited use of them is correct for the function I want to perform.
I have 9 tables which correspond to 9 different web based Ajax engined forms. I've worked hard on these, being my first time using Ajax, and I'm reasonably happy with them. Each time a user makes a change to whichever form they are filling out, the change is Ajaxed back to the DB and they get a confirmation or error response. Fairly straight forward. Each forms respective table has a "status" field, a "lastModified" field and a field I call "agRef" which is sort of like status but is null until the form reaches a certain stage, further along the process.
I have an additional table called "records" which is where all entries in any of the other tables, is listed so we can easily see what forms have been started, when their last changes were made and what status's they have. So here is where I believe the trigger part should work, so that I don't have to make updates to the "records" table in my php on every single transaction.
The "records" table is set out like this:
`uaID` int(11) NOT NULL AUTO_INCREMENT,
`uID` int(11) NOT NULL,
`appNo` int(11) NOT NULL,
`applicationKey` varchar(8) NOT NULL,
`appID` int(11) DEFAULT NULL,
`applicationName` varchar(64) NOT NULL,
`agRef` varchar(32) DEFAULT NULL,
`status` varchar(32) NOT NULL,
`dateStarted` int(11) NOT NULL,
`lastModified` int(11) NOT NULL,
Now all of these fields are populated at the same time the matching entry is inserted into which ever one of the other 9 tables the form connects to. A small example of one of the other 9 tables would look like this:
`appID` int(11) NOT NULL AUTO_INCREMENT,
`uID` int(11) NOT NULL,
`uaID` int(11) NOT NULL,
`status` varchar(32) NOT NULL DEFAULT 'Data Acquisition',
`agRef` varchar(32) DEFAULT NULL,
`groupName` varchar(64) DEFAULT NULL,
`shortTitle` varchar(64) DEFAULT NULL,
`recipient` varchar(64) DEFAULT NULL,
`partOfValCh` varchar(64) DEFAULT NULL,
`sector` varchar(64) DEFAULT NULL,
`subSector` varchar(64) DEFAULT NULL,
`topic` varchar(64) DEFAULT NULL,
<snip because this can go on for a lot of lines>
`dateStarted` int(11) NOT NULL,
`lastModified` int(11) NOT NULL,
agRef on both tables remain null for now, appID is null on the records table initially at the point of creation but is updated immediately as soon as the corresponding entry is made into the second table, where it is generated by auto increment and then a call is made back to my records table to insert the appID there.
The three things that will change from any of the data tables are the three fields "status", "agRef", "lastModified".
So I'm trying to create a trigger that will do this after each alteration/update to the data table, so that the data in my records table is consistent and accurate.
This is my first ever trigger set up attempt:
DELIMITER $$
CREATE TRIGGER `dataTableOne_to_records_sync` AFTER UPDATE ON `dataTableOne`
FOR EACH ROW BEGIN
UPDATE records (agRef, status, lastModified) VALUES (NEW.agRef, NEW.status, NEW.lastModified) WHERE appID = OLD.appID;
END$$
DELIMITER ;
I am trying to set this up through phpmyadmin, but it is returning an error telling me I have a syntax problem within my UPDATE line. I feel that it is an issue with the WHERE part - the appID is the one common element that ties the row in "records" to the row being updated/changed in "dataTableOne". How do I set this up correctly? Is my error something more serious, and am I running the risk of creating a huge mess, like a never ending loop? I'm a bit paranoid about doing this for the first time. Thanks in advance for help and advice.
UPDATE I have now tried a few other trigger attempts but although MySQL will accept them as being valid trigger syntax, they always seem to break the entire DB functionality. Can anyone help me with my trigger syntax to get it to work correctly? In the demo tables above, if the SECOND table gets updated at all, I want the three fields copied over into the FIRST table by the trigger. The three values I want copied across are "status", "agRef", and "lastModified".
My most recent failed attempt was this:
CREATE TRIGGER AIGltInq_sync AFTER INSERT ON app_AIGltInq
FOR EACH ROW
UPDATE records r
SET r.agRef = NEW.agRef
, r.status = NEW.status
, r.lastModified = NEW.lastModified
WHERE uaID = NEW.uaID;

Answer 1

I'm not at all familiar with that form of the UPDATE statement.
To change values of columns in rows, we'd typically write an UPDATE statement like this:
UPDATE records r
SET r.agRef = NEW.agRef
, r.status = NEW.status
, r.lastModified = NEW.lastModified
WHERE r.appId = OLD.appID
Reference: https://dev.mysql.com/doc/refman/5.5/en/update.html

Answer 2

Question withdrawn. Triggers are seriously best to avoid, as they tend to cause more breakages than they fix! Most recommendations tend towards handling the function with whatever scripting language you are using to talk with the DB. In my case this is PHP and PHP is now performing all of the functionality I was hoping to short-cut by using triggers. Lesson? Don't take short-cuts when wanting to do the job right. :)