Mailinglist Archive: opensuse-edu (179 mails)

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Re: [suse-linux-uk-schools] CCM Facility
  • From: "'Frank Shute'" <frank@xxxxxxxxxxxxxxxxxxxxx>
  • Date: Mon, 21 Jan 2002 20:18:52 +0000 (UTC)
  • Message-id: <20020121184744.A25853@xxxxxxxxxxxxxxxx>
On Mon, Jan 21, 2002 at 09:43:09AM +0000, Dan Kolb wrote:
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> On Monday 21 Jan 2002 09:35 am, Mark Evans wrote:
> > Chicken/Egg... Anyway isn't one of the meanings of SQL "Standard
> > Query Language" :)
>
> I thought it was Structured Query Language. But it should be pretty much the
> same whatever SQL database you use. However, opening a connection to a
> database isn't necessarily the same - you use different commands to open an
> PostgreSQL database compared to a MySQL database (at least I gather that from
> reading various Perl/PHP scripts)

With perl there is what's called a DBD/DBI (database
dependent/database independent) interface to accessing SQL databases.
You have one module (the DBD) that lies directly next to the database
which implements the calls supported by the database & on top of that
the more abstract DBI module through which you pass your SQL queries.
This makes it easy to migrate your code from one database to another
or write another DBI for some yet unsupported database.

This is how these people should have designed their system so that it
doesn't suck and customers can then use whatever SQL database they
like with minimal coding effort required by the company. If they'd
also then made the interface open then customers/db companies
could even write the database dependent bit themselves.

Different databases all implement the SQL'92 standard a bit
differently (it's abstract in parts) which is why you can have these
problems. I don't know if the standard has been updated lately or is
likely to be.

I don't know what the licensing terms for Oracle on Linux are but it
could be worth looking into for an educational establishment.

As I understand it, Oracle most completely implements the SQL standard
& is meant to be a good (though expensive) bit of software. Of the
free relational databases then postgresql supports more of the
standard & implements important things like transactions (although
MySQL might do these too now) then the others last time I looked.

As for application software that's equivalent to this stuff you're
looking into, I don't know off-hand.


--

Frank

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http://www.esperance-linux.co.uk/


Boob's Law:
You always find something in the last place you look.

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