On Jan 19, 2011, at 4:59 PM, Kevin Grittner wrote: > We've been running for about ten years on a framework which fires > triggers similar to database triggers in a Java tier close to the > database, and we're now trying to convert these to actual PostgreSQL > database triggers. Our biggest hitch at the moment is that we > defined a class of triggers we called "top" triggers, which only > fire from DML submitted by the application, not from DML issued by > other triggers. > > One significant use of this is to block direct modification of > summary data (either selected columns or entire tables) which are > supposed to be trigger maintained. It's not immediately obvious how > to accomplish this within PostgreSQL, although I'm probably missing > something. We're not tied to any particular methodology -- a > TG_DEPTH variable, if it existed, would do fine, for example. > > Any suggestions?
Most PLs include some session-specific storage. In PL/Perl, it is %_SHARED. Setting a flag there should do the trick. If you are using a PL which does not have such a notion (like plpgsql), you can add a call in your triggers to a function written in a PL which does support this. Alternatively, a C function which sets/checks a global flag would work as well. Cheers, M -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
