Hi, Adrian, On Mon, Dec 3, 2018 at 11:59 AM Adrian Klaver <adrian.klaver@xxxxxxxxxxx> wrote: > > On 12/3/18 9:53 AM, Igor Korot wrote: > >> So event triggers are associated with > >> events(www.postgresql.org/docs/9.6/event-trigger-matrix.html) in a > >> particular database. A rough description is that they are triggers on > >> changes to the system catalogs. > >> You could, I guess, create and drop them for each connection. To me it > >> would seem more efficient to create them once. You then have the choice > >> of leaving them running or using the ALTER command I posted previously > >> to ENABLE/DISABLE them. > > > > OK, so how do I do it? > > There is no "CREATE EVENT TRIGGER IF NOT EXIST". > > > > As I say - I'm trying to make it work from both ODBC and libpq > > connection (one at a time) > > Why? Just create the trigger once in a script. Event triggers are an > attribute of the database and stay with it until they are dropped. If > you want to turn then on and off use the ALTER EVENT TRIGGER > ENABLE/DISABLE. If you insist on recreating them on each connection then: > > https://www.postgresql.org/docs/10/sql-dropeventtrigger.html > DROP EVENT TRIGGER [ IF EXISTS ] name [ CASCADE | RESTRICT ] > CREATE EVENT TRIGGER ... I was hoping to create a software which will be just "install-and-use". No additional script running or database changes is required. But I will probably create it on every connection and delete on the disconnect (see above). > > > > >> > >>> > >>> Now the other question is - how to make it work? > >>> I can write the function code, compile it and place in the folder > >>> where my executable is (or it should be in some postgreSQL dir?) and > >>> then executing above code > >>> will be enough. Is this correct? > > > > Also - what about this? > > > > And why did you say that saving the SQL commend is not a good idea. > > > > What's better? > > See above. > > > > > Thank you. > > > >>> > >>>> > >>>>> > >>>>> And then in my C++ code I will continuously query this temporary table. > >>>> > >>>> Why a temporary table? They are session specific and if the session > >>>> aborts prematurely you will lose the information. > >>> > >>> Is there a better alternative? > >>> > >>> Thank you. > >>> > >>>> > >>>>> > >>>>> Or there is a better alternative on the algorithm? > >>>>> > >>>>> Thank you. > >>>>> > >>>>>>>> > >>>>>>> Thank you. > >>>>>>> > >>>>>> > >>>>>> > >>>>>> -- > >>>>>> Adrian Klaver > >>>>>> adrian.klaver@xxxxxxxxxxx > >>>>> > >>>> > >>>> > >>>> -- > >>>> Adrian Klaver > >>>> adrian.klaver@xxxxxxxxxxx > >>> > >> > >> > >> -- > >> Adrian Klaver > >> adrian.klaver@xxxxxxxxxxx > > > -- > Adrian Klaver > adrian.klaver@xxxxxxxxxxx
