Idea Summary
Currently there is no way to use the OLD or NEW specifiers on column level validations of an IG

We need to have such a feature in APEX so that the validations can be written more easily at the column level 

Use Case
Sometimes the OLD value of a cell needs to be compared with the new value of the cell in the IG and execute certain validations based on the OLD values

This is currently not possible . We obviously need to use a trigger and raise custom error message.

The problem with triggers is the concerned cell will not be highlighted with a red border. 

When the IG has lot of columns and rows pinpointing the error cell and the ability to navigate to the particular cell is a very sort after feature.

With the DB trigger raising exception only the row is marked but end users doesn't know which cell is of the concern from the error message.

Preferred Solution (Optional)
Provide a way in apex PL/SQL validations to access the current cells old and new values in the IG

for example :column_name.old and :column_name.new