Hi, good morning list
I'm writing a generic trigger in plpgsql to provide a system log to my system, but I'm stopped with the folow problem:
Example:
TABLE STRUCT:
table1
fldA VARCHAR
fldB VARCHAR
fldC VARCHAR
FUNCTION:
DECLARE
myrecord RECORD; -- record that will be storing field names from internal postres tables
fieldtest NAME; -- actual field name parsing
BEGIN
-- Generic function to automatize the log of changes
-- 1st, discover the field names from a table
FOR myrecord IN
SELECT
att.attname
FROM
pg_attribute att,
pg_class cls
WHERE
cls.oid = att.attrelid
AND att.attnum > 0
AND cls.relname = TG_RELNAME limit 1
LOOP
-- storing the actual field name
fieldtest = myrecord.attname;
/*
Here I'd like to do a parse in the 'fieldtest' variable to teste if the new value is diferent of the old value. The problem is:
Variable name: fieldtest
Variable content: fldA
How I can test the two records (new and old)?
-- new.fieldtest = fieldtest is not a field name to new record
-- new."fieldtest" = fieldtest is not a field name to new record
-- new.(fieldtest) = plpgsql can not do a parser in this
-- 'new.' || fieldtest = this is a string and can not be evaluate
*/
END LOOP;
-- Returning
RETURN NEW;
END;
Mauro Gonçalves
