Re: Alternatives to SQL ...

The world rejoiced as kleptog@svana.org (Martijn van Oosterhout) wrote:
> On Fri, May 24, 2002 at 12:43:36PM -0500, Gunther Schadow wrote:
>> - Sending a parse tree in XML for processing by the optimizer.
>>    This circumvents the SQL language and avoids the kinds of
>>    syntactic ideosyncrasies of SQL (e.g., where you put commas.)
>>    This is fairly trivial, but of course the question is, would it
>>    be worth it?
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> I don't know if you can design something in XML that is expressive
> and simple enough to compete with SQL. SQL is a simple language, why
> replace it with something unless it is demonstrably better.

SQL is good at providing "linear" queries; queries that indicate some
"linear" relationship between elements.

It is not so good at representing hierarchical relationships, which is
what XML is about.

The SQL:   SELECT FIELDS FROM TABLE
provides you with a linear list.

SQL isn't _nearly_ as nice at representing things that are naturally
expressed as trees.  It's pretty easy to have a DB schema where you
essentially have to submit an SQL query for every level of the tree.

And I am not ignoring JOIN here; that adds _some_ ability to join
together levels of trees, but not an unlimited ability.

The XML model fundamentally involves a hierarchy, and the 'query
method' involves passing in a function that reshapes that hierarchy.
I think there would be considerable value to that.

It certainly needs to be thought about before it is implemented, but
it's worth thinking about, to be sure.
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