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Re: Normalizing the ER model

From: K.Y. Fung <kyfung_at_hotmail.com>
Date: 21 Nov 2002 18:22:35 -0800
Message-ID: <c22bb40d.0211211822.2bb16043@posting.google.com>


hidders_at_hcoss.uia.ac.be (Jan Hidders) wrote in message news:<3dda1122$1_at_news.uia.ac.be>...
> In article <6278687.0211181428.75890385_at_posting.google.com>,
> Juan Pardillos <sicotom_at_eresmas.com> wrote:
> >
> >is it possible to apply the normalization process directly to the ER
> >model instead of apply it to the relational model?
>
> Yes, you can interpret a relationship as a relation and then apply the usual
> normalization rules. The same holds for the entity types but you have to
> take care of where the connections with the relationships go if you split
> then entity.
>
> -- Jan Hidders

I am just a beginner studying the process of normalization in OU Hong Kong. I don't understand how normalization can apply to ER model.

Correct me if I were wrong. ER model consists of Entity diagram, Entity type and its headings, Constraints and Assumptions. But Entity type only have an identifier without any keys. Entity type only shows there is a need to record information, and we draw a relation between entities base on the requirement we gather from user. But neither the entity heading nor the relation tell us how information in one entity is related with information in another entity. We can only infer it in the relational model when primary key / foreign key mechanism comes in. So how can normalization apply to ER model?

Regards,
King Yin Fung Received on Thu Nov 21 2002 - 20:22:35 CST

Original text of this message

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