I want to write a DB triger on a table which will trap the
column-name with old and new values which are updated.
The trigger should be written in a dynamic way to incorporate
any alteration (addition or deletion of columns) on the table.

Suppose the sal and deptno field of EMP table are updated.
Then the trigger will insert the column-name (sal, deptno)
along with old and new values into an another table.

So how to write this dynamic sql !! I've used dynamic sql
to achieve this, but while parsing the statement it throws
an error 'Bind Variable not declared' for the ld and :new
specifiers for the trigger.