Convert comma separated values to new child records

This is easy to do using a Rich Text Formula Field using the 3Q&S Techinque used as a button to invoke a script. The demo below contains three buttons named Demoize, Childize and Parentize place on the view record page. The Demoize button resets the demo and initializes the [Items] and [Quantities] to randomly generates values. The Childize button takes the [Items] and [Quantities] in the Parent record and transfers the values to individual child records. The Parentize button reverses this process.

Here is a screenshot after pressing the Demoize button and generating random [Items] and [Quantities] in the Parent record:



Here is a screenshot after next pressing the Childize button and transferring the [Items] and [Quantities] values in the Parent record to individual Child records:



Pressing the Parentize button will reverse the Childize process.

Here is the demo in which you can test and even create your own record:

Childize / Parentize ~ View Parent Record #1
https://haversineconsulting.quickbase.com/db/bpcesdwqm?a=dr&rid=1

Pastie Database
https://haversineconsulting.quickbase.com/db/bgcwm2m4g?a=dr&rid=726

Notes:

(1) This demo has features beyond what you asked for but are appropriate for a demo that hopefully will not require a lot of maintenance on my part.

(2) The same core approach can be used to perform bulk operations and a selection or records rather than an individual record.

(3) You probably need some additional logic and features to deal with edge case in your data or other feature that were not articulated.