Comment by RaftPeople

> "There is no sensible way to represent tree-like data in that [RDBMS] environment" - there is endless literature covering storing data structures in relational schemas. The complaint seems to be to just be "it's complicated".

Ya, this one really confused me. Tree-like data is very easy to model in an RDBMS in the same way it is in memory, with parent+child node pointers/links/keys.

It's possible he was thinking of one of these challenges:

1-SQL doesn't easily handle the tree structure. You can make it work but it's square peg round hole.

2-He mentioned JSON so maybe he was really thinking in terms of different types of data for each node. Meaning one node might have some text data and the next node might have a list or dictionary of values. That is tougher in RDBMS.