[xquery-talk] the stupidity of using SQL as a query language for JSON

daniela florescu dflorescu at me.com
Mon Jun 1 13:50:59 PDT 2015

> On Jun 1, 2015, at 12:29 PM, Michael Kay <mike at saxonica.com> wrote:
>> And BTW Michael, if SQL  would be good for querying hierarchical data, why in the world did we waste 16 years building XQuery !???
> It didn’t say it was good for the purpose. I said it was possible. The only reason I can think of for actually doing it is that there’s a fair bit of software out there that likes to access its data using SQL.

The paper I wrote with Donald Kossmann in 1997 about mapping XML into relations ALSO included the 
SQL queries equivalent to the simplest XPath expressions.

Those SQL queries are HORRENDOUSLY complicated.

I don’t care how many tools use SQL. 

Two things come to my mind:

1. Nobody will write such SQL queries (that result from the mapping JSON-> tables or XML -> tables) and

2. Even if you manage to write them somehow, the queries are SO complex, the relational database engines are not capable 
of dealing with them — not even Oracle.
(Jay here https://www.linkedin.com/profile/view?id=955015 wrote his PhD about such SQL queries, and I think he wakes
up with nightmares even now…)

Tools will need to adapt to a new query language for JSON. Or we need new tools. Or we abandon JSON.

That’s as simple as that.

Best regards
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