Absolutely agreed. Based on what we're seeing, maintaining this in anything other than a relational manner will become a major headache. This is still relational data, not non-relational.

To get it back, include it in the original data set, bring back the information of the parent record and all the child records together a single data set. That means that you'll see six copies of the parent data if there are six child records, but you should be able to deal with that on the app side of things. One call, one data set, still relational storage. Or, if you really want to, it's added overhead, but you could pivot the results so that you return a single column of data, just IDs if that's all that's needed, for the child data. That'll work too.