Re: Avoiding duplications in tables

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От shreedhar
Тема Re: Avoiding duplications in tables
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Msg-id 012001c2f1d6$5a9e3bd0$1201a8c0@a4005
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Ответ на Avoiding duplications in tables  (Deepa K <kdeepa@midascomm.com>)
Список pgsql-general
Hi Deepa,

Let me know that
1) Is tables  ApplicationNumber and ApplicationManager are same ?
2) Why do you have more than one referential key between two tables, Which
will makes process very slow.

If answer to the first question as 'yes' and answer to the second question
as 'I can change it to single referential key'
You can look the following design which will wipe out redundancy.

(1)     tablename : versions

            versionnumber - string

(2)    tablename : applications

            applicationnumber - integer
            other details

(3)    tablename : applicationnumber    -- CHANGED

          ApplicaitonNumberId Integer
          versionnumber  - string
          applicationnumber - integer

(4)    tablename : profilemanager    -- CHANGED

        ApplicationNumberId - Integer
        ProfileId - Integer
           other details

(5)    tablename : profiles    -- CHANGED

         ProfileId - Integer
          versionnumber - string
           profilename      - string

Primary key :
---------------

(1)    versions : versionnumber
(2)    applicationmanager ( ApplicationNumber) :  ApplicationNumberId    --
CHANGED
(3)    applications : applicationnumber
(4)    profilemanager :  ProfileId, ApplicationNumberId     -- CHANGED
(5)    profiles : ProfileId     -- CHANGED

Relations :
-----------

(1)    versionnumber of 'applicationmanager/ApplicationNumber' referes to
versionnumber of

          'versions' table.
(2)    applicationnumber of 'applicationmanager/ApplicationNumber' referes
to  applicationnumber of 'applications' table.
(3)    ApplicationNumberId of 'profilemanager' referes to
ApplicationNumberId of 'applicationmanager'.  -- CHANGED
(4)    ProfileId of  'profilemanager' referes to ProfileId of 'profiles'. --
CHANGED
(5)    versionnumber of 'profiles' referes to versionnumber of  'versions'.

I Think this design will serve your purpose (which will move redundancy).

Sreedhar Baskararaju

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----- Original Message -----
From: "Deepa K" <kdeepa@midascomm.com>
To: <pgsql-general@postgresql.org>
Sent: Monday, March 24, 2003 12:33 PM
Subject: [GENERAL] Avoiding duplications in tables


> Hi All,
>                 I have the following tables.
>
> (1)     tablename : versions
>
>             versionnumber - string
>
> (2)    tablename : applications
>
>             applicationnumber - integer
>             other details
>
> (3)    tablename : applicationnumber
>
>           versionnumber  - string
>           applicationnumber - integer
>
> (4)    tablename : profilemanager
>
>           versionnumber - string
>           profilename       - string
>           applicationnumber - integer
>            other details
>
> (5)    tablename : profiles
>
>           versionnumber - string
>            profilename      - string
>
> Primary key :
> ---------------
>
> (1)    versions : versionnumber
> (2)    applicationmanager : versionnumber, applicationnumber
> (3)    applications : applicationnumber
> (4)    profilemanager : veriosnnumber, profilename, applicationnumber
> (5)    profiles : versionnumber, profilename
>
> Relations :
> -----------
>
> (1)    versionnumber of 'applicationmanager' referes to versionnumber of
>
>           'versions' table.
> (2)    applicationnumber of 'applicationmanager' referes to
>           applicationnumber of 'applications' table.
> (3)    versionnumber and applicationnumber of 'profilemanager' referes
>           to versionnumber and applicationnumber of
> 'applicationmanager'.
> (4)    versionnumber and profilename of 'profilemanager' referes ot
>           versionnumber and profilename of 'profiles'.
> (5)    versionnumber of 'profiles' referes to versionnumber of
>            'versions'.
>
> In the above design I can able to see duplication of data in all the
> tables. If I take out a id out of all these tables to make reference, is
>
> that problem will solve. Is that is
> a correct approach.
>
> Can any one help me.
>
> regards,
> Deepa  K
>
>
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> TIP 6: Have you searched our list archives?
>
> http://archives.postgresql.org


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