[topicmapmail] Expressive capabilities of Topic Maps

[Thomas B. Passin]

[ <jalgermissen@topicmapping.com>]

> No, I disagree that creating a table is more costly than creating
> a new association type. A relational table and an association type
> are essentially the same thing and a topic map system 'of any use'
> (all implementors forgive me,please ;-) would IMHO have to do
> all the kind of indexeing on associations (by type, by roles, by
> players) that an RDBMS does on tables. You definitely cannot get
> away with connecting some objects by mere references.
>

I agree, but creating a table is equivalent to creating a new type, but we
can augment an association by attaching another role to it - without
creating a new type (and even if we have to create a new role type, that is
a simpler creation than a new table).  So that is a difference, which seems
significant to me.

> > Sure you can get multiple classification.
>
> Sure, you can create a single huge table (TABLE TOPIC) and
> represent class-instance-ness in another table, connecting
> entities of type topic....but if that's good ER design.....;-)
>

That's not the only way ...

Cheers,

Tom P