Re: Is mysql a RDBMS ?

"Heikki Tuuri" <Heikki.Tuuri_at_innodb.com> wrote in message news:0d12b.203$yu.178_at_read3.inet.fi...
> Morten,
>
> "Morten Gulbrandsen" <Morten.Gulbrandsen_at_rwth-aachen.de> kirjoitti
viestissä
> news:60ca69db.0308210016.822e230_at_posting.google.com...
> > Hello,
> >
> > I have only read Elmasri/Navathe and I find it nearly impossible
> > to implement any non-trivial Enhanced Entity relationship diagram
> > in MySQL,
> > according to the mailing list, important foreign key constraints are
> > not supported,
>
> foreign key constraints are supported in MySQL. Where did you find on the
> mailing list the claim that they are not? I do not remember seeing that
> claim for a long time. InnoDB does not support ON ... SET DEFAULT, but
>
[snip]
> > ===
> > "Morten Gulbrandsen" <mgu_at_owi-aachen.de> wrote:
> ...
> > It is the most popular SQL server,
> > so I can start to believe that alone MySQL is no RDBMS,
> > unless it is combined with another programming language,
> >
> > Is this true ?
> >
> > From Elmasri:
> >
> > To qualify as a genuine relational DBMS,
> > a system must have at least the following properties:
> >
> > 1.) It must store data as relations such that each column is
> > independently identified by its column name and the ordering of rows
> > is immaterial.
>
> This holds for MySQL.

Are you saying that the following works with MySQL?

select somecharfield name, someintfield id from sometable
union
select anotherintfield id, anothercharfield name from someothertable
;

> > 2.) The operations available to the user, as well as those used
> > internally by the system, should be true relational operations; that
> > is, they should be able to generate new relations from old relations.
>
> This holds for MySQL.

Consider the following relation, AB:

A        B
=        =
1        1
1        2
1        3

Are you saying that the following statement results in a relation in MySQL?

select A
from AB
;

> > 3.) The system must support at least one variant of the JOIN
> > operation.
>
> This holds for MySQL.

Well, 1 out of 3 is better than none, I guess. Received on Sun Aug 24 2003 - 16:45:47 CEST