Re: Help: Many to Many relationships

Brian Peasland wrote:

> Peter,
>
> Unlike Access, Oracle doesn't care about the cardinality of your
> relationships. There is no way to specify a 1:1, 1:M, or M:N
> relationship in Oracle. So the answer to your question is that there is
> no joining table required. You can use one if you want though...
>
> HTH,
> Brian
>
> Peter Mount wrote:
> >
> > Hello
> >
> > I have just recently started to learn Oracle at my school.
> >
> > I just need to know if Oracle handles Many to Many relationships in the ER
> > Diagram (as part of the Data Modelling process) in the same way as MS
> > Access - i.e. with a joining table in between the two tables with the many
> > to many relationship with each other.
> >
> > Thanks
> >
> > Peter Mount
> > pmount_at_optusnet.com.au
>
> --
> ========================================
> Brian Peasland
> Raytheons Systems at
> USGS EROS Data Center
> These opinions are my own and do not
> necessarily reflect the opinions of my
> company!
> ========================================

Brian,
the Oracle ERD diagrammer (part of Designer) does allow, and does care! Point is that you can model it, but the rdbms doesn't support it, that (by default) supports 1:M relations, so you will end up with a third table (usually called the intersection table).

Peter,
I wasn't aware access was a) a database, and b) allows modeling --
Met vriendelijke groet/kind regards,

Frank van Bortel
Technical consultant Oracle Received on Wed Feb 23 2000 - 18:00:20 CST