Ignoring the academic point of view for a moment, if you have any sort of table of related data, surely, they have some sort of relationship or queryable attrib

Ignoring the academic point of view for a moment, if you have any sort of table of related data, surely, they have some sort of relationship or queryable attributes. Find me all users with X... (SELECT * users WHERE X,...). In practice, I've found that you don't really query documents. Can you? Sure, I suppose, but I found myself reinventing what those databases do for me. Sorry, I know that's not a formal explanation. But it is a practical day-to-day one. It's easier for me, and I think others too albeit with practice, to simply write a line of SQL to get what I want.