reHi Jan,
Sorry, this one slipped under my radar. I wasn't ignoring you.
Your arguments are well thought out but the fact of the matter is that until
we change the major databases of the world from RDBMS to something more
suited to XML then all you will ever be doing is providing an insulation
layer. Yes, you may feel that you can create a richer query in XML but if
you are talking to a RDBMS then someone or something has to translate that
into SQL. If I so it myself instead of letting an XML translator built into
the engine do it then I am in control and can optimize it the way I see fit.
I'm not arguing against talking to applications in XML. I'm against building
that additional layer into the database engine itself. It's code that many
people don't want or need and for those that do want it, they can easily add
it. As I've stated before, unlike the code bloat of Oracle and MS, with
MySQL, if you want it, you have the option of adding it yourself without
forcing it on others.
You are correct that SQL is limited, but so are all other languages short of
binary for communicating with computers. But as I stated in an earlier
message, SQL gives me the most powerful way to-date of retrieving data from
an RDBMS. XLM might hide the complexity of it but it will not be more
powerful.
Cal
http://www.calevans.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Jan Dvorak
Sent: Monday, February 26, 2001 12:58 AM
To: Cal Evans
Cc: Ed Carp; [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: Re: XML support under mySQL
Cal,
Cal Evans wrote:
>
> Glorious Sunday morning greetings to you Jan,
>
> No, XML is a format for 2 different applications, usually 2 totally
separate
> applications, to be able to exchange data.
> It is not an appropriate choice
> for storing large amounts of data that will have to be queried.
But the XML markup is just a manifestation of a deeper structure: trees.
Trees are more general than tuples, a piece of XML can convey more
information
than a piece of a relational table.
> Nor is it an appropriate choice of language for talking to an RDBMS.
> Outside of the fact that it can be extremely verbose,
...it compresses magnificiently...
> we already have a perfectly good language for that, SQL.
> SQL is a language for committing data to a storage mechanism
> and retrieving the data back. It is superior to XML in those tasks.
No.
SQL is limited by the linear structure of tables.
If you need to retrieve/store more complex information,
you need to place several SELECTs/INSERTs in a row.
Compare this to the rich structure of trees XML is based on.
I know I can represent a Request for Quote in one XML document,
but the same thing would take me five tables of a relational database.
I know I can represent a Quote - which is a result of the Request for Quote
query -
with just one XML document, while the same thing would take me at least four
relational tables.
> Again, if you have need to talk to your RDBMS via XML then a thin wrapper
> written in the language of your choice is the proper way to go. This
allows
> you to do your job without bloating my application with unnecessary code.
I'm already tired of thin wrappers.
Plus they are not exactly efficient; the two overheads are in place and
hogging:
1. The client/server communication overhead, even if we go locally thru a
socket;
2. The SQL overhead of having to parse, understand and optimize a query can
kill you on thousands of
queries.
As a rule, new functionalities in MySQL are optional.
You don't have to enable them.
> And I also disagree with your statement that there is no difference
between
> metadata and data. there most certainly is. But that's a discussion for
> another thread.
It's always data.
You call it metadata if it describes some other data.
But on its own, it's data in the first place.
> humbly,
> Cal
> http://www.calevans.com
Yours,
Jan
> p.s. another reason not to include it is NOBODY wants to distract the
MySQL
> coders from getting 4.0 frozen and out the door! :)
Hey, eventually a good reason against XML in MySQL!
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Jan Dvorak
> Sent: Sunday, February 25, 2001 10:13 AM
> To: Ed Carp
> Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]
> Subject: Re: XML support under mySQL
>
> Ed Carp wrote:
> >
> > Gorjan Todorovski ([EMAIL PROTECTED]) writes:
> >
> > > Since XML is a way to exchange data...and it is protocol/platform
> indepdnent
> > > there is a very good reason to have XML docuemts going in and out the
> >
> > No, it's not. You store *data* in a database, *not* metadata. Do you
> understand the difference?
>
> There is no difference.
> What is metadata in one context, is data in another context.
> It's just a matter of your standpoint, which can change with time.
>
> XML is a format to store/exchange data.
>
> Jan Dvorak
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