Re: QUESTION: Modeling problem using ERWIN/SQL

ggarcia_at_mipos2.intel.com (Gilbert Garcia) writes:
> Hello ERWIN/SQL users,
>
> CARD CARD_DEVICE
> -------- -----------
> card_id card_type
> card_type device_type
>
> I want to create subtypes of CARD and use DEVICE_TYPE
> as the discriminator. Does ERWIN/SQL allow me to do so?? If so, how?!?
>

Here's how: edit CARD, remove attribute card_type and any relationships in effect with CARD_DEVICE. then select the broken line with a blob at one end (a non-identifying 1:many relation). draw this line from CARD_DEVICE to CARD. as a result, ER/Win will add the card_type and device_type attributes to CARD.

be sure card_type and device_type are declared primary keys in CARD_DEVICE. because this new relation is non-identifying, card_type and device_type in CARD are not inherited by any relations which depend on CARD.

Long live ER/Win!

-- 
Dave Mausner, Senior Consultant / Datalogics Inc / Chicago IL / 312-266-4450
dlm_at_dlogics.com                                 Motto: Just show me the code