Re: parent-child relation with two children...

From: tal_mcmahonAThotmail.com <tal_mcmahon_at_hotmail.com>
Date: Fri, 1 Aug 2008 13:35:21 -0700 (PDT)
Message-ID: <54f1c503-fb66-4345-9bcf-ac93532ed388@x35g2000hsb.googlegroups.com>


Hi,
If I read this correctly, your saying

you have an entity, The entity is either Live or Preview, and the entity has versions.

I have seen this before, and I believe it is an error in your model.

what you really want here is the entity table and 2 extension tables of entity one for Live and one for preview.

Like this

Entity(pk_entity),
EntityLiveVersionExtension(pk_entity,LiveVersionID,version), EntityPreviewVersionExtension(pk_entity,PreviewVersionID,version),

All of them have the primary key of pk_Entity and the extensions are a one --> zero or one relationships

 This is one of the ways to handle Object Inheritance within a relational database. I am guessing you have (or at least could have) an entityBase and a PreviewENtity and a LiveEntity.

HTH Tal Received on Fri Aug 01 2008 - 15:35:21 CDT

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