From: Rick James
Date: June 22 2012 11:54pm
Subject: RE: Triggers and column names
List-Archive: http://lists.mysql.com/mysql/227732
Message-Id: <2E7DD7ADE53B044C8C8BCD9C5829E1EB14876083AF@SP2-EX07VS01.ds.corp.yahoo.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable

Suggest using a script to read information_schema and construct the TRIGGER=
.  After all, the fields are not going to change from one invocation of the=
 trigger to the next, so don't have the "dynamic" code inside the trigger.

> -----Original Message-----
> From: Hal?sz S?ndor [mailto:hsv@stripped]
> Sent: Thursday, June 21, 2012 5:05 PM
> To: mysql
> Subject: Re: Triggers and column names
>=20
> >>>> 2012/06/21 17:06 -0500, Gael Martinez >>>>
> I'm getting that done today thru a large static trigger script and I
> would like something more dynamic...
> <<<<<<<<
> For that it is needful to look up the table in
> INFORMATION_SCHEMA.COLUMNS, and, yes, you can look up the field names--
> but then what will you do with the character strings that are the field
> names? use PREPARE and EXECUTE for the comparisons, being ware of NULL?
>=20
> In MySQL help it is written that for its own purposes MySQL actually
> tracks all the information that you crave, but it nowhere is written
> that a BEFORE-UPDATE trigger can make use of it. Maybe UDF, but I know
> naught about that.
>=20
> Since BEFORE is called on every attempt, successful or not, maybe AFTER
> would be better.
>=20
>=20
> --
> MySQL General Mailing List
> For list archives: http://lists.mysql.com/mysql
> To unsubscribe:    http://lists.mysql.com/mysql