[Tfug] Inheritance in RDBMS's (PostgreSQL, Oracle, et al.)

[Terence Rudkin]

On Thu, Aug 6, 2009 at 9:08 PM, Bexley Hall <bexley401 at yahoo.com> wrote:

> Hi Terence,
>
> > If the base type is well
> > defined addition can be easy.  Doing  versioning can
> > become a snap  because base columns are there and
> > additional columns are there based on version.
>
> I'm not sure I understand how this is a consequence of inheritance?
> Could you elaborate?

I was referring to typical evolution of schema and relations, where there is
the discovery that new data points are to be collected for a relation.  The
table is based on the base type and as you evolve the schema new types are
created to represent the new view of the data model.    The Application then
can tell by the object returned the version of the object and thus the code
path to properly work with the data.  Generally this would be done by
dummy'ing up the missing data.

Hope this helps

>
>
> >> Any general issues to avoid or exploit to take better
> >> advantage of this capability?
> > Create constructor and helper methods to make  access even
> > smother.
>
> Thanks!
> --don
>
>
>
>
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