[Dbix-class] Auditing - (was Optimistic locking)

[Dan Horne]

> 
> If you're doing that, can you bear in mind that it'd rock if we could
> extend
> that later to add change auditing please? :)
> 
> (I was going to implement that but the project I needed it for got
> cancelled
> so it's gone onto the back-burner for the mo)
> 

What would auditing consist of? For instance, I wrote a simple Perl script
to generate triggers for Oracle tables that would record all changes against
the base table in an audit table with the following definition

        lkau_id       -- the audit table key
        username      -- the user who has made the change
        table_name    -- the name of the table being altered
        tbl_key       -- the primary key value. Composite key values are
                         separated by the delimiter defined in the
                         KEY_DELIMITER constant
        column_name,  -- the name of the column that is changing
        before_value, -- the value before the change. New rows have no
                         old values
        after_value,  -- the value after the change. Deleted rows have no
                      -- after value
        updated       -- when the change was made

Are you wanting something similar as a DBIC component? I guess there would
be a performance hit - each update would need to select the old values
again, but I guess that anyone who wants audit would realise that there is
an overhead anyway.

I'm not sure how username would be deduced, or even explicitly set.

Dan