Обсуждение: Re: [GENERAL] Trigger documentation? Need more examples.. pleeeze.. ;-)
Re: [GENERAL] Trigger documentation? Need more examples.. pleeeze.. ;-)
От
Henrique Pantarotto
Дата:
Yeah, I really need to do "external stuff" (messing with external files, executing programs), and if I understood it correctly, PL/pgSQL can't do that, right? Thanks! On qui, 19 ago 1999, you wrote: > perhaps using PL/pgSQL is easier? in the doc there are examples, > also, the one in the /test is rather complex (too complex?). > > However, PL/pgSQL may not be able to to external stuff, even C > can do that. -- I have the same problem, anybody'd ideas? > > > > > >From: Henrique Pantarotto <scanner@cepa.com.br> > >To: pgsql-general@postgreSQL.org > >Subject: [GENERAL] Trigger documentation? Need more examples.. pleeeze.. > >;-) > >Date: Thu, 19 Aug 1999 11:40:11 -0300 > > > >Hello PostgreSQL friends! > > > >I'm new to PostgreSQL, but I've been using MySQL/mSQL for a long time now. > >I > >switched to PostgreSQL mostly because of it's features: triggers, > >specially. > > > >I've studied, compiled and tried the examples from the crontrib/spi > >directory. > >They all worked, but without some kind of documentation it is really hard > >to > >understand how things really work, and how I can create my own stuff. > > > >In the "Programmer's Guide", there's a whole chapter documenting the SPI > >library, but I didn't find any documentation of the functions directly > >related > >to TRIGGERS (library "triggers.h"), like: "TRIGGER_FIRED_BY_UPDATE()", > >"CurrentTriggerData->tg_newtuple", etc... > > > >Is this documentation available somewhere? > > > >----- > > > >I have this table: > > > >CREATE TABLE users ( > > userid INT4 NOT NULL, > > fullname CHAR(40), > > username CHAR(20), > > password CHAR(13) > >) > > > > > >Using the examples from contrib/spi, I guess I can manage to create an > >INSERT > >and DELETE trigger. But I'm not sure how to create an UPDATE one. > > > >Let's suppose someone updates both fields "username" and "password". HOW > >from > >the trigger I know which fields changed. Is it possible to get the older > >and newer values and compare them? > > > >This UPDATE trigger doesn't need to modify it's own new inserted data, but > >it > >has to modify external data (create/delete files at my Linux filesystem, > >rename directories, etc..). > > > >Is such thing possible? Someone has an example of this? ;-) > > > > > >Thanks a lot! > > > >Regards from Brazil! > > > > > >-- > >Henrique Pantarotto > >CEPAnet Internet Provider > >webmaster / analista de sistemas > >Email: scanner@cepa.com.br > >Tel: (011) 5506-8477 > >Cel: (011) 9706-3444 > >LINUX FRIEND > > > >************ > > > > > _______________________________________________________________ > Get Free Email and Do More On The Web. Visit http://www.msn.com -- Henrique Pantarotto CEPAnet Internet Provider webmaster / analista de sistemas Email: scanner@cepa.com.br Tel: (011) 5506-8477 Cel: (011) 9706-3444 LINUX FRIEND