Re: Question about accessing current row data inside trigger
От | Jim Buttafuoco |
---|---|
Тема | Re: Question about accessing current row data inside trigger |
Дата | |
Msg-id | 20050308232604.M14503@contactbda.com обсуждение исходный текст |
Ответ на | Question about accessing current row data inside trigger (pw <p.willis@telus.net>) |
Список | pgsql-interfaces |
have you looked in the contrib directory (Postgresql 7.4.6). I just checked and the dbmirror/pending.c looks like some good code to follow. Jim ---------- Original Message ----------- From: pw <p.willis@telus.net> To: pgsql-interfaces@postgresql.org Sent: Tue, 08 Mar 2005 14:57:24 -0800 Subject: [INTERFACES] Question about accessing current row data inside trigger > *previously posted this to pgsql-general* > > -Hello, > - > -I have a trigger function written in C. > -The trigger function is called via: > - > -CREATE TRIGGER after_update AFTER UPDATE ON some_table > - FOR EACH ROW EXECUTE PROCEDURE my_trigger_function(); > - > - Since the trigger is called after each row update the actual > -row data > -should be available in some way to the trigger. > - > - What functionality (SPI ?) do I use to use the column values -from the > -current row in the actual trigger? > - > - Does SPI_cursor_fetch automatically give me the current trigger -row or > -do I need to query again for the proper row? > - > -thanks for any insight, > - > -Peter > > I am now using : > > TupleTableSlot *t = (TupleTableSlot *) PG_GETARG_POINTER(0); > bool isnull; > > char *buffer=(char *)DatumGetPointer(GetAttributeByName(t, > "some_column_name", &isnull)); > > The pointer always comes back NULL though there is data > in the column. > > I'm still not sure this is the correct way to access > the data from the updated row. > > Is this the correct way to get a string back from > the data in the column named 'some_column_name'? > > Do I have the correct TupleTableSlot pointer? > > Thanks for any insight, > > Peter > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) ------- End of Original Message -------
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