Logging trigger

[Bart Pietercil]

Hi List, Ruslan

I am thinking about the feasibility of this:

inside an after update trigger it would like to do

Loop over all the fields of a given table comparing the new values  
with the old values.
This way I can write to a log table the old values and the new values.
Is there a way to "read" what fields will be modified? Or do I have  
to loop over all the field names. I know I can get all the fields of  
a table inside a cursor with the SHOW COLUMNS OF Table command. But  
this feels like a way that would generate way too much overhead. When  
only one field is updated I still would need to loop over all the  
fields, comparing their old values to the new values.

Can I use the name retrieved with the show columns command combined  
with new (or old) like this

1) declare cursor = SHOW FIELDS OF table
2)How do I get to the name column of this cursor ????
3) I set local variable thisField = value of current row of cursor 
(column('name'))
4) now I should be able to say IF new.thisField IS NOT EQUAL TO  
old.thisField then
	INSERT INTO tbl_log(f1,f2,...)VALUES(old.ThisField,new.ThisField,.....)

Is this somehow possible.

It seems to me we are very close to this but not yet possible.:-(

Please advice

TIA

Bart Pietercil
PS: other ways of getting to a workable logging solution are of  
course welcome. But the solution would need to be contained within  
Valentina