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Re: Designing a structure

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  To: comp.databases,comp.lang.
"Stefan Ram" <ram@zedat.fu-berlin.de> wrote in message 
news:database-20080503180716@ram.dialup.fu-berlin.de...
> David Segall <david@address.invalid> writes:
>>For most purposes I want to communicate with a family or
>>business at its "home" address. For example, "Fred and Betty
>>Bloggs" or "Acme Widgets" have a specified street address and
>>telephone number. It is possible that the Bloggs family has a
>>holiday house or I have to deal with Acme Widgets at more than
>>one location.
>
>  If a family can have n houses, that is a 1:n-relation, and its
>  implementation is being described in every RDBMS textbook.
>
>>I also need information about individuals such as mobile phone
>>numbers and birthdays but I don't want to duplicate shared home
>>and business addresses and telephone numbers. For example,
>>Betty Bloggs could work for Acme Widgets and share a town house
>>and a country house with Fred.
>
>  Then have one table for persons, one for houses and one for
>  the n:m-relation (standard textbook material).
>
>>have been frustrated by the address books in many applications
>>that insist you supply all the details for every individual.
>
>  If you do not want a field to be mandatory, you are free
>  to design so.
>
>  Just design which entities and relations you want to
>  model and which attributes are mandatory and which not.
>  Then implement this and you are done.

I tend to agree. The basic entities are fairly clearcut: addresses, personal 
(individual/business) info, phone numbers, email addresses. There are simply 
going to be lots of relationships, and in addition they are going to be 
named relationships (so one can designate a work phone number as opposed to 
a personal phone number, or a primary home address as opposed to a cottage), 
so the join tables will often have at least one extra attribute.

As far as people sharing addresses, say, like a couple. Well, that's not 
really a database problem, per se. The address itself only needs to be 
stored once - there will simply be two PersonInfo-Address relationships. To 
avoid having to enter the data twice is really more a function of the 
application that one designs to enter (and display) the data. In other 
words, I'd write the application so that it is quite flexible at 
searching/retrieving entities and allowing new links (relationships) to be 
established.

Myself I would keep personal relationships (e.g. couple, family, roommates 
etc) entirely separate. That is, if you want to say that Person A is married 
to Person B, use a separate join table for that. Because personal 
relationships do not invariably imply any other linkages.

To recap, I see most of the work being asociated with the interface, not the 
actual database.

AHS

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Designing a structure for "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
  Re: Designing a structure "Ed Prochak" <ed.prochak@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
    Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
      Re: Designing a structure "Martin Gregorie" <martin.gregorie@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
        Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
          Re: Designing a structure "Ed Prochak" <ed.prochak@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
          Re: Designing a structure "Arved Sandstrom" <arved.sandstrom@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
      Re: Designing a structure "Ed Prochak" <ed.prochak@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
        Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
          Re: Designing a structure "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
            Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
              Re: Designing a structure "David Cressey" <david.cressey@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
                Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
              Re: Designing a structure "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
                Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
                Re: Designing a structure "Ed Prochak" <ed.prochak@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
                Re: Designing a structure "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
                Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
            Re: Designing a structure "Gene Wirchenko" <gene.wirchenko@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
          Re: Designing a structure "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
  Re: Designing a structure "ram" <ram@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
    Re: Designing a structure "Arved Sandstrom" <arved.sandstrom@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
      Re: Designing a structure "ram" <ram@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
        Re: Designing a structure "Arved Sandstrom" <arved.sandstrom@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
          Re: Designing a structure "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
      Re: Designing a structure "David Segall" <david.segall@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
        Re: Designing a structure "Marco" <marco@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
          Re: Designing a structure "Arved Sandstrom" <arved.sandstrom@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000
  Re: Designing a structure "Marco" <marco@THRWHITE.remove-dii-this> - 2011-04-27 15:21 +0000

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