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Re: Hierarchical Relationship

From: Gene Wirchenko <genew_at_shuswap.net>
Date: 2000/03/03
Message-ID: <38bf0301.7784057@news.shuswap.net>#1/1

Bernard Peek <Bernard_at_shrdlu.com> wrote:

>In article <89liln$7h0$1_at_news1.xs4all.nl>, John Smith
><someone_at_microsoft.com> writes
>>Hi,
>>
>>I am trying to make a Familytree in Access.
>>In simplified form I have made
>>2 tables: TblPerson and TblParents
>>and 1 Querie: QryPerson&Parents.
>>
>>In TblPerson I have the basic properties of a person (ID, Name, sexe etc.).
>>In TblParents I have 3 fields: Person_ID, Father_ID and Mother_ID
>>
>>TblParents is linked 1-to-1 with TblPerson by [TblPerson].[ID] and
>>[TblParents].[Person_ID].
>>The other 2 fields (Father_ID and Mother_ID) are fields that look up their
>>values in TblPerson.
>>
>>QryPerson&Parents joins the 2 tables so that I get 1 recordset of a person
>>including who his parents are.
>>
>>So far so good but there is one problem. I'd like to build in some
>>validation. For example; one should not be able to select a distant
>>offspring or a distant ancestor as a parent.
>
>You can probably do enough validation by looking at the date of
>birth/death and making sure that nobody marries someone born more than a
>hundred years earlier.

     That latter is not an absolute constraint.

>Other validation rules could get a little tricky, I do know someone
>whose family tree has a loop in it. It wasn't legal but it happened
>anyway.

     How could a loop be possible? I think you mean something else: what?

     Here's an unusual case for length of generations. It's from Stan McLean's "The History of the O'Keefe Ranch" (ISBN: 0-919873-08-1), p. 140:

     Casey (b. 1970). It may be interesting to point out again that his paternal grandfather was born in 1837.

Sincerely,

Gene Wirchenko

Computerese Irregular Verb Conjugation:

     I have preferences.
     You have biases.
     He/She has prejudices.
Received on Fri Mar 03 2000 - 00:00:00 CST

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