Обсуждение: Inherited Table

Anyone know how inherited tables are shown on an ERD... both the table
and the connector (if any)?

What I am looking for is how to draw this in the diagram.

Peter

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Peter Harvey wrote:
>
> Anyone know how inherited tables are shown on an ERD... both the table
> and the connector (if any)?
>
> What I am looking for is how to draw this in the diagram.

An old S-Designor does it so:

Hannu Krosing wrote:
> 
> Peter Harvey wrote:
> >
> > Anyone know how inherited tables are shown on an ERD... both the table
> > and the connector (if any)?
> >
> > What I am looking for is how to draw this in the diagram.
> 
> An old S-Designor does it so:
> 

Yes. But pgsql does not support multiple inheritance (from what I can
tell) so the extra symbol along the ref line ("can be"/"must be") seems
silly. I am thinking that I should draw the new table slightly diff in
some way just as is done with Views. However; some purests would freak.
<Hmmm>

Thanks

Peter

Peter Harvey wrote: >Yes. But pgsql does not support multiple inheritance (from what I can >tell)...

In fact it does:
 create table child (col1 text) inherits (parent1, parent2);

Identically named and typed columns in the parents are merged.

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