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Old 02-28-08, 02:44
marcel0000 marcel0000 is offline
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db design issueL relation overruling, inheritence, ...

Hi!

In my application I have the following scenario:

I need to assign multiple properties to a house. But as more houses are added I want my users to be able to assign properties to lets say a group and all houses in that group now share the same properties. But the problem is that there can be a house in a group that does not share one or more properties defined in that group, or just needs to add some extra properties.

So I came op with:

- 1 group has many properties and a property can be assigned to many groups
- 1 group has many houses and a house only belongs to one group
- a house can have many properties and a property can be assigned to many houses

I'm still not feeling comfortable with this since (1) a need to programmicly retrieve all properties and override it with specific house-property relations and (2) a need some 'inactive' column on the house-property relation to exclude properties defined in the group.

So any ideas how I do should resolve this problem? I have been looking at the concept of storing inheritence in database but I'm not realy sure about it.

Thanks in advance! :-)
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Old 02-28-08, 07:48
r937 r937 is offline
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how to resolve what problem?

that design sounds okay to me
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Old 02-28-08, 08:00
marcel0000 marcel0000 is offline
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Well I thought there meight be a better solution for this issue :-)

I mean, creating a database design that actualy forces that kind of 'property overloading' instead of relying on the software implementation to follow that kind of behaviour.

I'v been using this design for a lot more projects in the past but I'd like to know if there are better alternatives :-)

Always learning ;-)
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