Unfortunately, the bit you're trying to change is located in "old code": code that's still inherited from SQL Ledger, which means you probably need a few extra rounds to make it work in all cases. But from what I found out so far is that you're looking to change the query in IC.pm:435 to include your new column and the $dbh->execute() line right below to include the value of the column to be set. That value is held in $form->{<name-of-the-entry-field-in-the-form>}.
In general, this is probably a reasonable way to do this. It ensures that you can later add appropriate constraints, etc. and the datatype can be whatever you like. There is a second way to do it, which is *not* guaranteed to continue to work as-is after we redo the logic for the parts (though you can customize the logic easily enough to bring it back) which is:
1) use the add_custom_field() stored procedure
2) Customize the user interface to handle that
There are a couple things to keep in mind with this second approach:
1) It is designed only for very light-weight customizations. In other words it will *only* give you a field which is stored in/retrieved from the database
2) It is only supported for text types.
To use this approach you;d run the following query in pgAdmin or psql:
SELECT * FROM add_custom_field('parts', 'my_field_name', 'text');
Then customize the screen (in bin/
ic.pl's form_header and form_footer functions).
Best Wishes,
Chris Travers