Re: Inheritance mapping in a RDBMS

On 16 Feb 2004 10:16:19 -0800, neo55592_at_hotmail.com (Neo) wrote:

>> What I am trying to do is, map an inheritance hierarchy in a relational
>> database system.
>>
>> Example:
>> Let's say you want to describe in a relational database, a collection of
>> soundcarriers that consists of records, cassetes, dat-tapes en cds.
>> (extremely simplified example, possible domain values between brackets)
>>
>> Should I use a couple of tables:
>>
>> soundcarrier (id, content [music, speech], label_description)
>> record (id, material [aluminium, glass, vinyl], speed[33,45,78])
>> cassete (id, length [45, 90, 120])
>> dat (id, brand[sony, maxwell], sample_freq[44,48])
>> cd (id, brand [sony, maxwell])
>
>For an alternate solution using a small experimental db, see examples
>www.xdb1.com/Example/Ex102.asp and www.xdb1.com/Example/Ex004.asp
>XDb allows a thing to have multiple classifications, variable number
>of properties and inherit properties from it's classes.
>
>For example, suppose thing1 isa soundcarrier and record. Then in
>effect, thing1.label and thing1.material will return values, where as
>thing1.sampleFreq won't since thing1 was not classified as a dat.
>
>If you would like to set up an example db, please post some
>representative data.

Do you happen to know when that xdb thing was created? That's a LOT like a science fair project I did in high school. Received on Wed Feb 18 2004 - 05:34:52 CET