specify column to match on

[timbeach]

In our email thread leading up to the creation of this tool, I made an error when I said that we would always match on primary key.
I have since been made aware that there are times where we must match on another column. For example, the question table from source db needs to match to the question table on target db on the column: question.code rather than the primary key of question.id.
Is there any way to modify the tool so we can specify which column to match on?

Note: the matching column is always a unique index. no need for the ability to handle multiples.