Allow the Table Output step to specify fields of the target table.
This will make it easier to build mappings but also allows us to take data through not meant for that particular table.
You can solve referential integrity issues with this technique by using 2 or more Table Output steps sequentially rather then parallel.
Parallel inserts into 2 referentially connected tables can and will cause racing conditions and database errors.
The "problem" currently is that only the fields which are in the table can be sent to a table output, so the output hops of table output can only contain these fields. In update/insert and update it's now the case that you can specify the columns to use towards the database... but the hop which flows out of the insert/update keeps all input fields. This latter approach allows to use multiple insert/update steps in sequence.
Suggestion would be to have an extra switch button on the dialog of table output for "implicit"/old or "explicit"/new columns, and an extra tab containing the specified columns in a table.