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Stubborn Question: Maintain Referential Integrity of Redundant data

Discussion in 'Information Technology' started by Sam, Jul 28, 2006.

  1. Sam

    Sam
    Expand Collapse
    Guest

    Is there a way to maintain real Referential Integrity of Redundant
    fields in two tables?

    I have searched the newsgroup and it seems the general advice is to not
    have redundant data at all. But sometimes space is less a concern than
    computing power, so not having to join tables all the time to view data
    is preffered.

    Any comment is appreciated. Thank you.

    -Sam
     
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  3. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    No, you have to code for it.

    The problem with denormalised data is maintaining integrity, this relies on
    competent programming.


    --

    Terry Kreft


    "Sam" <sampahkertas@yahoo.com> wrote in message
    news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > Is there a way to maintain real Referential Integrity of Redundant
    > fields in two tables?
    >
    > I have searched the newsgroup and it seems the general advice is to not
    > have redundant data at all. But sometimes space is less a concern than
    > computing power, so not having to join tables all the time to view data
    > is preffered.
    >
    > Any comment is appreciated. Thank you.
    >
    > -Sam
    >
     
  4. Allen Browne

    Allen Browne
    Expand Collapse
    Guest

    You are aware that storing redundant data violates the most basic
    normalization rules?

    If your reason for doing this is, "not having to join tables all the time,"
    my guess is that you don't understand the amount of work you are taking on
    to verify that these redundant copies are always managed with perfect
    accuracy in every possible scenario. You could lean about all the pitfalls
    by spending a few months falling into them all (if you ever did actually
    find all of them that way), but it would be *much* more profitable for you
    to spend your time understanding what normalization is, why these rules
    exist, and how much work they save you in the long term.

    Kinda like the ancient ship captain who had two chronometers, and therefore
    never really knew which one was right.

    --
    Allen Browne - Microsoft MVP. Perth, Western Australia.
    Tips for Access users - http://allenbrowne.com/tips.html
    Reply to group, rather than allenbrowne at mvps dot org.

    "Sam" <sampahkertas@yahoo.com> wrote in message
    news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > Is there a way to maintain real Referential Integrity of Redundant
    > fields in two tables?
    >
    > I have searched the newsgroup and it seems the general advice is to not
    > have redundant data at all. But sometimes space is less a concern than
    > computing power, so not having to join tables all the time to view data
    > is preffered.
    >
    > Any comment is appreciated. Thank you.
    >
    > -Sam
     
  5. Sam

    Sam
    Expand Collapse
    Guest

    Wow, strong responses. OK, I got it, I won't pursue this matter any
    further. I asked because I want to know if there's any quick fix for
    the problem. I guess not. :)

    Thank you.

    -Sam
     
  6. Craig Alexander Morrison

    Craig Alexander Morrison
    Expand Collapse
    Guest

    It also relies on the data redundancy being managed by the database and not
    the application(s).

    Jet in this regard is of no use and one should be using DB2, Oracle or SQL
    Server.

    --
    Slainte

    Craig Alexander Morrison
    Crawbridge Data (Scotland) Limited
    "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > No, you have to code for it.
    >
    > The problem with denormalised data is maintaining integrity, this relies
    > on
    > competent programming.
    >
    >
    > --
    >
    > Terry Kreft
    >
    >
    > "Sam" <sampahkertas@yahoo.com> wrote in message
    > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >> Is there a way to maintain real Referential Integrity of Redundant
    >> fields in two tables?
    >>
    >> I have searched the newsgroup and it seems the general advice is to not
    >> have redundant data at all. But sometimes space is less a concern than
    >> computing power, so not having to join tables all the time to view data
    >> is preffered.
    >>
    >> Any comment is appreciated. Thank you.
    >>
    >> -Sam
    >>

    >
    >
     
  7. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    Expand and explain please as you appear to be wrong.

    --

    Terry Kreft


    "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > It also relies on the data redundancy being managed by the database and

    not
    > the application(s).
    >
    > Jet in this regard is of no use and one should be using DB2, Oracle or SQL
    > Server.
    >
    > --
    > Slainte
    >
    > Craig Alexander Morrison
    > Crawbridge Data (Scotland) Limited
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > > No, you have to code for it.
    > >
    > > The problem with denormalised data is maintaining integrity, this relies
    > > on
    > > competent programming.
    > >
    > >
    > > --
    > >
    > > Terry Kreft
    > >
    > >
    > > "Sam" <sampahkertas@yahoo.com> wrote in message
    > > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >> Is there a way to maintain real Referential Integrity of Redundant
    > >> fields in two tables?
    > >>
    > >> I have searched the newsgroup and it seems the general advice is to not
    > >> have redundant data at all. But sometimes space is less a concern than
    > >> computing power, so not having to join tables all the time to view data
    > >> is preffered.
    > >>
    > >> Any comment is appreciated. Thank you.
    > >>
    > >> -Sam
    > >>

    > >
    > >

    >
    >
     
  8. Craig Alexander Morrison

    Craig Alexander Morrison
    Expand Collapse
    Guest

    How do you manage data redundancy in Jet?

    Remember Data Redundancy should be avoided, if it cannot it needs to be
    managed by the DBMS.

    Only the larger DBMSs can perform this management.

    In Jet you can only do it at the application level and this is high risk by
    comparison.

    In general as I said above you should avoid Data Redundancy and Data
    Interdependence but this cannot always be achieved and still maintain a
    business system.

    OLAP is a case in point, it is by its very nature storing redundant data but
    it is managed by the DBMS.


    --
    Slainte

    Craig Alexander Morrison
    Crawbridge Data (Scotland) Limited
    "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > Expand and explain please as you appear to be wrong.
    >
    > --
    >
    > Terry Kreft
    >
    >
    > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    >> It also relies on the data redundancy being managed by the database and

    > not
    >> the application(s).
    >>
    >> Jet in this regard is of no use and one should be using DB2, Oracle or
    >> SQL
    >> Server.
    >>
    >> --
    >> Slainte
    >>
    >> Craig Alexander Morrison
    >> Crawbridge Data (Scotland) Limited
    >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    >> > No, you have to code for it.
    >> >
    >> > The problem with denormalised data is maintaining integrity, this
    >> > relies
    >> > on
    >> > competent programming.
    >> >
    >> >
    >> > --
    >> >
    >> > Terry Kreft
    >> >
    >> >
    >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >> >> Is there a way to maintain real Referential Integrity of Redundant
    >> >> fields in two tables?
    >> >>
    >> >> I have searched the newsgroup and it seems the general advice is to
    >> >> not
    >> >> have redundant data at all. But sometimes space is less a concern than
    >> >> computing power, so not having to join tables all the time to view
    >> >> data
    >> >> is preffered.
    >> >>
    >> >> Any comment is appreciated. Thank you.
    >> >>
    >> >> -Sam
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >
     
  9. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    I'm not sure what you mean by "Only the larger DBMSs can perform this
    management." could you expand on that please.


    --

    Terry Kreft


    "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    > How do you manage data redundancy in Jet?
    >
    > Remember Data Redundancy should be avoided, if it cannot it needs to be
    > managed by the DBMS.
    >
    > Only the larger DBMSs can perform this management.
    >
    > In Jet you can only do it at the application level and this is high risk

    by
    > comparison.
    >
    > In general as I said above you should avoid Data Redundancy and Data
    > Interdependence but this cannot always be achieved and still maintain a
    > business system.
    >
    > OLAP is a case in point, it is by its very nature storing redundant data

    but
    > it is managed by the DBMS.
    >
    >
    > --
    > Slainte
    >
    > Craig Alexander Morrison
    > Crawbridge Data (Scotland) Limited
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > > Expand and explain please as you appear to be wrong.
    > >
    > > --
    > >
    > > Terry Kreft
    > >
    > >
    > > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    in
    > > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > >> It also relies on the data redundancy being managed by the database and

    > > not
    > >> the application(s).
    > >>
    > >> Jet in this regard is of no use and one should be using DB2, Oracle or
    > >> SQL
    > >> Server.
    > >>
    > >> --
    > >> Slainte
    > >>
    > >> Craig Alexander Morrison
    > >> Crawbridge Data (Scotland) Limited
    > >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > >> > No, you have to code for it.
    > >> >
    > >> > The problem with denormalised data is maintaining integrity, this
    > >> > relies
    > >> > on
    > >> > competent programming.
    > >> >
    > >> >
    > >> > --
    > >> >
    > >> > Terry Kreft
    > >> >
    > >> >
    > >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    > >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >> >> Is there a way to maintain real Referential Integrity of Redundant
    > >> >> fields in two tables?
    > >> >>
    > >> >> I have searched the newsgroup and it seems the general advice is to
    > >> >> not
    > >> >> have redundant data at all. But sometimes space is less a concern

    than
    > >> >> computing power, so not having to join tables all the time to view
    > >> >> data
    > >> >> is preffered.
    > >> >>
    > >> >> Any comment is appreciated. Thank you.
    > >> >>
    > >> >> -Sam
    > >> >>
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >
     
  10. Douglas J. Steele

    Douglas J. Steele
    Expand Collapse
    Guest

    I'm guessing, Terry, that Craig's talking about using triggers to manage the
    redundant data. However, it would be nice if he answered.

    --
    Doug Steele, Microsoft Access MVP
    http://I.Am/DougSteele
    (no private e-mails, please)


    "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    > I'm not sure what you mean by "Only the larger DBMSs can perform this
    > management." could you expand on that please.
    >
    >
    > --
    >
    > Terry Kreft
    >
    >
    > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    > message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    >> How do you manage data redundancy in Jet?
    >>
    >> Remember Data Redundancy should be avoided, if it cannot it needs to be
    >> managed by the DBMS.
    >>
    >> Only the larger DBMSs can perform this management.
    >>
    >> In Jet you can only do it at the application level and this is high risk

    > by
    >> comparison.
    >>
    >> In general as I said above you should avoid Data Redundancy and Data
    >> Interdependence but this cannot always be achieved and still maintain a
    >> business system.
    >>
    >> OLAP is a case in point, it is by its very nature storing redundant data

    > but
    >> it is managed by the DBMS.
    >>
    >>
    >> --
    >> Slainte
    >>
    >> Craig Alexander Morrison
    >> Crawbridge Data (Scotland) Limited
    >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    >> > Expand and explain please as you appear to be wrong.
    >> >
    >> > --
    >> >
    >> > Terry Kreft
    >> >
    >> >
    >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    > in
    >> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    >> >> It also relies on the data redundancy being managed by the database
    >> >> and
    >> > not
    >> >> the application(s).
    >> >>
    >> >> Jet in this regard is of no use and one should be using DB2, Oracle or
    >> >> SQL
    >> >> Server.
    >> >>
    >> >> --
    >> >> Slainte
    >> >>
    >> >> Craig Alexander Morrison
    >> >> Crawbridge Data (Scotland) Limited
    >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    >> >> > No, you have to code for it.
    >> >> >
    >> >> > The problem with denormalised data is maintaining integrity, this
    >> >> > relies
    >> >> > on
    >> >> > competent programming.
    >> >> >
    >> >> >
    >> >> > --
    >> >> >
    >> >> > Terry Kreft
    >> >> >
    >> >> >
    >> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    >> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >> >> >> Is there a way to maintain real Referential Integrity of Redundant
    >> >> >> fields in two tables?
    >> >> >>
    >> >> >> I have searched the newsgroup and it seems the general advice is to
    >> >> >> not
    >> >> >> have redundant data at all. But sometimes space is less a concern

    > than
    >> >> >> computing power, so not having to join tables all the time to view
    >> >> >> data
    >> >> >> is preffered.
    >> >> >>
    >> >> >> Any comment is appreciated. Thank you.
    >> >> >>
    >> >> >> -Sam
    >> >> >>
    >> >> >
    >> >> >
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >
     
  11. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    Hi Doug,

    Yep, That's exactly what I thought he was talking about and if so, was the
    reason why I was going to say that essentially he was wrong.




    --

    Terry Kreft


    "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message
    news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    > I'm guessing, Terry, that Craig's talking about using triggers to manage

    the
    > redundant data. However, it would be nice if he answered.
    >
    > --
    > Doug Steele, Microsoft Access MVP
    > http://I.Am/DougSteele
    > (no private e-mails, please)
    >
    >
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    > > I'm not sure what you mean by "Only the larger DBMSs can perform this
    > > management." could you expand on that please.
    > >
    > >
    > > --
    > >
    > > Terry Kreft
    > >
    > >
    > > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    in
    > > message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    > >> How do you manage data redundancy in Jet?
    > >>
    > >> Remember Data Redundancy should be avoided, if it cannot it needs to be
    > >> managed by the DBMS.
    > >>
    > >> Only the larger DBMSs can perform this management.
    > >>
    > >> In Jet you can only do it at the application level and this is high

    risk
    > > by
    > >> comparison.
    > >>
    > >> In general as I said above you should avoid Data Redundancy and Data
    > >> Interdependence but this cannot always be achieved and still maintain a
    > >> business system.
    > >>
    > >> OLAP is a case in point, it is by its very nature storing redundant

    data
    > > but
    > >> it is managed by the DBMS.
    > >>
    > >>
    > >> --
    > >> Slainte
    > >>
    > >> Craig Alexander Morrison
    > >> Crawbridge Data (Scotland) Limited
    > >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > >> > Expand and explain please as you appear to be wrong.
    > >> >
    > >> > --
    > >> >
    > >> > Terry Kreft
    > >> >
    > >> >
    > >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    wrote
    > > in
    > >> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > >> >> It also relies on the data redundancy being managed by the database
    > >> >> and
    > >> > not
    > >> >> the application(s).
    > >> >>
    > >> >> Jet in this regard is of no use and one should be using DB2, Oracle

    or
    > >> >> SQL
    > >> >> Server.
    > >> >>
    > >> >> --
    > >> >> Slainte
    > >> >>
    > >> >> Craig Alexander Morrison
    > >> >> Crawbridge Data (Scotland) Limited
    > >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > >> >> > No, you have to code for it.
    > >> >> >
    > >> >> > The problem with denormalised data is maintaining integrity, this
    > >> >> > relies
    > >> >> > on
    > >> >> > competent programming.
    > >> >> >
    > >> >> >
    > >> >> > --
    > >> >> >
    > >> >> > Terry Kreft
    > >> >> >
    > >> >> >
    > >> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    > >> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >> >> >> Is there a way to maintain real Referential Integrity of

    Redundant
    > >> >> >> fields in two tables?
    > >> >> >>
    > >> >> >> I have searched the newsgroup and it seems the general advice is

    to
    > >> >> >> not
    > >> >> >> have redundant data at all. But sometimes space is less a concern

    > > than
    > >> >> >> computing power, so not having to join tables all the time to

    view
    > >> >> >> data
    > >> >> >> is preffered.
    > >> >> >>
    > >> >> >> Any comment is appreciated. Thank you.
    > >> >> >>
    > >> >> >> -Sam
    > >> >> >>
    > >> >> >
    > >> >> >
    > >> >>
    > >> >>
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >
     
  12. Craig Alexander Morrison

    Craig Alexander Morrison
    Expand Collapse
    Guest

    No, I do not think so.

    But tell me what exactly you think I am wrong about as you did not address
    the question

    >> >> How do you manage data redundancy in Jet?


    You indicated to the OP that they could do "it" in code, however that could
    only be at application level and this is easily subverted.

    Or are you actually saying that I should calculate the balances of 10
    million bank accounts to arrive at the customer deposits total in order to
    have a pure relational database with no redundant data.

    You know I always try to start with a pure design so that I know what
    redundancy we need to manage.

    BTW If you are using Jet then I would strongly recommend that you stay with
    the "pure" design.

    --
    Slainte

    Craig Alexander Morrison
    Crawbridge Data (Scotland) Limited
    "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    news:OCXRxxFmGHA.3732@TK2MSFTNGP05.phx.gbl...
    > Hi Doug,
    >
    > Yep, That's exactly what I thought he was talking about and if so, was the
    > reason why I was going to say that essentially he was wrong.
    >
    >
    >
    >
    > --
    >
    > Terry Kreft
    >
    >
    > "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message
    > news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    >> I'm guessing, Terry, that Craig's talking about using triggers to manage

    > the
    >> redundant data. However, it would be nice if he answered.
    >>
    >> --
    >> Doug Steele, Microsoft Access MVP
    >> http://I.Am/DougSteele
    >> (no private e-mails, please)
    >>
    >>
    >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    >> > I'm not sure what you mean by "Only the larger DBMSs can perform this
    >> > management." could you expand on that please.
    >> >
    >> >
    >> > --
    >> >
    >> > Terry Kreft
    >> >
    >> >
    >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    > in
    >> > message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    >> >> How do you manage data redundancy in Jet?
    >> >>
    >> >> Remember Data Redundancy should be avoided, if it cannot it needs to
    >> >> be
    >> >> managed by the DBMS.
    >> >>
    >> >> Only the larger DBMSs can perform this management.
    >> >>
    >> >> In Jet you can only do it at the application level and this is high

    > risk
    >> > by
    >> >> comparison.
    >> >>
    >> >> In general as I said above you should avoid Data Redundancy and Data
    >> >> Interdependence but this cannot always be achieved and still maintain
    >> >> a
    >> >> business system.
    >> >>
    >> >> OLAP is a case in point, it is by its very nature storing redundant

    > data
    >> > but
    >> >> it is managed by the DBMS.
    >> >>
    >> >>
    >> >> --
    >> >> Slainte
    >> >>
    >> >> Craig Alexander Morrison
    >> >> Crawbridge Data (Scotland) Limited
    >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    >> >> > Expand and explain please as you appear to be wrong.
    >> >> >
    >> >> > --
    >> >> >
    >> >> > Terry Kreft
    >> >> >
    >> >> >
    >> >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > wrote
    >> > in
    >> >> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    >> >> >> It also relies on the data redundancy being managed by the database
    >> >> >> and
    >> >> > not
    >> >> >> the application(s).
    >> >> >>
    >> >> >> Jet in this regard is of no use and one should be using DB2, Oracle

    > or
    >> >> >> SQL
    >> >> >> Server.
    >> >> >>
    >> >> >> --
    >> >> >> Slainte
    >> >> >>
    >> >> >> Craig Alexander Morrison
    >> >> >> Crawbridge Data (Scotland) Limited
    >> >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    >> >> >> > No, you have to code for it.
    >> >> >> >
    >> >> >> > The problem with denormalised data is maintaining integrity, this
    >> >> >> > relies
    >> >> >> > on
    >> >> >> > competent programming.
    >> >> >> >
    >> >> >> >
    >> >> >> > --
    >> >> >> >
    >> >> >> > Terry Kreft
    >> >> >> >
    >> >> >> >
    >> >> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    >> >> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >> >> >> >> Is there a way to maintain real Referential Integrity of

    > Redundant
    >> >> >> >> fields in two tables?
    >> >> >> >>
    >> >> >> >> I have searched the newsgroup and it seems the general advice is

    > to
    >> >> >> >> not
    >> >> >> >> have redundant data at all. But sometimes space is less a
    >> >> >> >> concern
    >> > than
    >> >> >> >> computing power, so not having to join tables all the time to

    > view
    >> >> >> >> data
    >> >> >> >> is preffered.
    >> >> >> >>
    >> >> >> >> Any comment is appreciated. Thank you.
    >> >> >> >>
    >> >> >> >> -Sam
    >> >> >> >>
    >> >> >> >
    >> >> >> >
    >> >> >>
    >> >> >>
    >> >> >
    >> >> >
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >
     
  13. Craig Alexander Morrison

    Craig Alexander Morrison
    Expand Collapse
    Guest

    I may be Scottish but I am watching England in the World Cup and after that
    the Formula One Grand Prix of Canada.

    ....I would love to know why Terry thinks I am wrong, I would wholeheartedly
    agree I was wrong if I was using Jet and then expecting Access at the
    application level to manage the redundancy.

    I use DB2 as the backend and therefore all necessary redundancy is strictly
    managed as you say via Triggers and Triggered Actions.

    To quote from Chris Date "Incidentally, we do not mean to suggest that all
    redundancy can or necessarily should be eliminated...However, we do mean to
    suggest that any such redundancy should be carefully controlled-that is the
    DBMS should be aware of it, if it exists and should assume responsibility
    for "propagating updates"."

    --
    Slainte

    Craig Alexander Morrison
    Crawbridge Data (Scotland) Limited

    "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message
    news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    > I'm guessing, Terry, that Craig's talking about using triggers to manage
    > the redundant data. However, it would be nice if he answered.
    >
    > --
    > Doug Steele, Microsoft Access MVP
    > http://I.Am/DougSteele
    > (no private e-mails, please)
    >
    >
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    >> I'm not sure what you mean by "Only the larger DBMSs can perform this
    >> management." could you expand on that please.
    >>
    >>
    >> --
    >>
    >> Terry Kreft
    >>
    >>
    >> "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    >> message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    >>> How do you manage data redundancy in Jet?
    >>>
    >>> Remember Data Redundancy should be avoided, if it cannot it needs to be
    >>> managed by the DBMS.
    >>>
    >>> Only the larger DBMSs can perform this management.
    >>>
    >>> In Jet you can only do it at the application level and this is high risk

    >> by
    >>> comparison.
    >>>
    >>> In general as I said above you should avoid Data Redundancy and Data
    >>> Interdependence but this cannot always be achieved and still maintain a
    >>> business system.
    >>>
    >>> OLAP is a case in point, it is by its very nature storing redundant data

    >> but
    >>> it is managed by the DBMS.
    >>>
    >>>
    >>> --
    >>> Slainte
    >>>
    >>> Craig Alexander Morrison
    >>> Crawbridge Data (Scotland) Limited
    >>> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >>> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    >>> > Expand and explain please as you appear to be wrong.
    >>> >
    >>> > --
    >>> >
    >>> > Terry Kreft
    >>> >
    >>> >
    >>> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    >> in
    >>> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    >>> >> It also relies on the data redundancy being managed by the database
    >>> >> and
    >>> > not
    >>> >> the application(s).
    >>> >>
    >>> >> Jet in this regard is of no use and one should be using DB2, Oracle
    >>> >> or
    >>> >> SQL
    >>> >> Server.
    >>> >>
    >>> >> --
    >>> >> Slainte
    >>> >>
    >>> >> Craig Alexander Morrison
    >>> >> Crawbridge Data (Scotland) Limited
    >>> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >>> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    >>> >> > No, you have to code for it.
    >>> >> >
    >>> >> > The problem with denormalised data is maintaining integrity, this
    >>> >> > relies
    >>> >> > on
    >>> >> > competent programming.
    >>> >> >
    >>> >> >
    >>> >> > --
    >>> >> >
    >>> >> > Terry Kreft
    >>> >> >
    >>> >> >
    >>> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    >>> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >>> >> >> Is there a way to maintain real Referential Integrity of Redundant
    >>> >> >> fields in two tables?
    >>> >> >>
    >>> >> >> I have searched the newsgroup and it seems the general advice is
    >>> >> >> to
    >>> >> >> not
    >>> >> >> have redundant data at all. But sometimes space is less a concern

    >> than
    >>> >> >> computing power, so not having to join tables all the time to view
    >>> >> >> data
    >>> >> >> is preffered.
    >>> >> >>
    >>> >> >> Any comment is appreciated. Thank you.
    >>> >> >>
    >>> >> >> -Sam
    >>> >> >>
    >>> >> >
    >>> >> >
    >>> >>
    >>> >>
    >>> >
    >>> >
    >>>
    >>>

    >>
    >>

    >
    >
     
  14. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    Well, you're obviously not going to actually say why you said what you did
    so I'll go along with my assumption.

    The reason why I believe that what you said was essentially wrong is that I
    believe you are referring to using triggers to maintain RI between redundant
    data in tables.

    My reasoning goes like this:-
    Stored procedures are not part of the inbuilt DRI of the database
    Triggers are only a special sort of SPROC therefore they are not part of
    the inbuilt DRI of the database.

    To put it another way triggers have to be coded, they are a developed item
    and are part of the application rather than the dbms.

    The rest of your post seems to involve a fantasy conversation or a
    conversation with someone other than myself.

    --

    Terry Kreft


    "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    message news:OjcvpSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    > No, I do not think so.
    >
    > But tell me what exactly you think I am wrong about as you did not address
    > the question
    >
    > >> >> How do you manage data redundancy in Jet?

    >
    > You indicated to the OP that they could do "it" in code, however that

    could
    > only be at application level and this is easily subverted.
    >
    > Or are you actually saying that I should calculate the balances of 10
    > million bank accounts to arrive at the customer deposits total in order to
    > have a pure relational database with no redundant data.
    >
    > You know I always try to start with a pure design so that I know what
    > redundancy we need to manage.
    >
    > BTW If you are using Jet then I would strongly recommend that you stay

    with
    > the "pure" design.
    >
    > --
    > Slainte
    >
    > Craig Alexander Morrison
    > Crawbridge Data (Scotland) Limited
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:OCXRxxFmGHA.3732@TK2MSFTNGP05.phx.gbl...
    > > Hi Doug,
    > >
    > > Yep, That's exactly what I thought he was talking about and if so, was

    the
    > > reason why I was going to say that essentially he was wrong.
    > >
    > >
    > >
    > >
    > > --
    > >
    > > Terry Kreft
    > >
    > >
    > > "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message
    > > news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    > >> I'm guessing, Terry, that Craig's talking about using triggers to

    manage
    > > the
    > >> redundant data. However, it would be nice if he answered.
    > >>
    > >> --
    > >> Doug Steele, Microsoft Access MVP
    > >> http://I.Am/DougSteele
    > >> (no private e-mails, please)
    > >>
    > >>
    > >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    > >> > I'm not sure what you mean by "Only the larger DBMSs can perform this
    > >> > management." could you expand on that please.
    > >> >
    > >> >
    > >> > --
    > >> >
    > >> > Terry Kreft
    > >> >
    > >> >
    > >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    wrote
    > > in
    > >> > message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    > >> >> How do you manage data redundancy in Jet?
    > >> >>
    > >> >> Remember Data Redundancy should be avoided, if it cannot it needs to
    > >> >> be
    > >> >> managed by the DBMS.
    > >> >>
    > >> >> Only the larger DBMSs can perform this management.
    > >> >>
    > >> >> In Jet you can only do it at the application level and this is high

    > > risk
    > >> > by
    > >> >> comparison.
    > >> >>
    > >> >> In general as I said above you should avoid Data Redundancy and Data
    > >> >> Interdependence but this cannot always be achieved and still

    maintain
    > >> >> a
    > >> >> business system.
    > >> >>
    > >> >> OLAP is a case in point, it is by its very nature storing redundant

    > > data
    > >> > but
    > >> >> it is managed by the DBMS.
    > >> >>
    > >> >>
    > >> >> --
    > >> >> Slainte
    > >> >>
    > >> >> Craig Alexander Morrison
    > >> >> Crawbridge Data (Scotland) Limited
    > >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > >> >> > Expand and explain please as you appear to be wrong.
    > >> >> >
    > >> >> > --
    > >> >> >
    > >> >> > Terry Kreft
    > >> >> >
    > >> >> >
    > >> >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > > wrote
    > >> > in
    > >> >> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > >> >> >> It also relies on the data redundancy being managed by the

    database
    > >> >> >> and
    > >> >> > not
    > >> >> >> the application(s).
    > >> >> >>
    > >> >> >> Jet in this regard is of no use and one should be using DB2,

    Oracle
    > > or
    > >> >> >> SQL
    > >> >> >> Server.
    > >> >> >>
    > >> >> >> --
    > >> >> >> Slainte
    > >> >> >>
    > >> >> >> Craig Alexander Morrison
    > >> >> >> Crawbridge Data (Scotland) Limited
    > >> >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > >> >> >> > No, you have to code for it.
    > >> >> >> >
    > >> >> >> > The problem with denormalised data is maintaining integrity,

    this
    > >> >> >> > relies
    > >> >> >> > on
    > >> >> >> > competent programming.
    > >> >> >> >
    > >> >> >> >
    > >> >> >> > --
    > >> >> >> >
    > >> >> >> > Terry Kreft
    > >> >> >> >
    > >> >> >> >
    > >> >> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    > >> >> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >> >> >> >> Is there a way to maintain real Referential Integrity of

    > > Redundant
    > >> >> >> >> fields in two tables?
    > >> >> >> >>
    > >> >> >> >> I have searched the newsgroup and it seems the general advice

    is
    > > to
    > >> >> >> >> not
    > >> >> >> >> have redundant data at all. But sometimes space is less a
    > >> >> >> >> concern
    > >> > than
    > >> >> >> >> computing power, so not having to join tables all the time to

    > > view
    > >> >> >> >> data
    > >> >> >> >> is preffered.
    > >> >> >> >>
    > >> >> >> >> Any comment is appreciated. Thank you.
    > >> >> >> >>
    > >> >> >> >> -Sam
    > >> >> >> >>
    > >> >> >> >
    > >> >> >> >
    > >> >> >>
    > >> >> >>
    > >> >> >
    > >> >> >
    > >> >>
    > >> >>
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >
     
  15. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    Triggers are specialised SPROCS they do not form part of the inbuilt DRI,
    that's why I say you're wrong. They _are_ part of the application


    --

    Terry Kreft


    "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    message news:OQS9zSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    > I may be Scottish but I am watching England in the World Cup and after

    that
    > the Formula One Grand Prix of Canada.
    >
    > ...I would love to know why Terry thinks I am wrong, I would

    wholeheartedly
    > agree I was wrong if I was using Jet and then expecting Access at the
    > application level to manage the redundancy.
    >
    > I use DB2 as the backend and therefore all necessary redundancy is

    strictly
    > managed as you say via Triggers and Triggered Actions.
    >
    > To quote from Chris Date "Incidentally, we do not mean to suggest that all
    > redundancy can or necessarily should be eliminated...However, we do mean

    to
    > suggest that any such redundancy should be carefully controlled-that is

    the
    > DBMS should be aware of it, if it exists and should assume responsibility
    > for "propagating updates"."
    >
    > --
    > Slainte
    >
    > Craig Alexander Morrison
    > Crawbridge Data (Scotland) Limited
    >
    > "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message
    > news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    > > I'm guessing, Terry, that Craig's talking about using triggers to manage
    > > the redundant data. However, it would be nice if he answered.
    > >
    > > --
    > > Doug Steele, Microsoft Access MVP
    > > http://I.Am/DougSteele
    > > (no private e-mails, please)
    > >
    > >
    > > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > > news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    > >> I'm not sure what you mean by "Only the larger DBMSs can perform this
    > >> management." could you expand on that please.
    > >>
    > >>
    > >> --
    > >>
    > >> Terry Kreft
    > >>
    > >>
    > >> "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    in
    > >> message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    > >>> How do you manage data redundancy in Jet?
    > >>>
    > >>> Remember Data Redundancy should be avoided, if it cannot it needs to

    be
    > >>> managed by the DBMS.
    > >>>
    > >>> Only the larger DBMSs can perform this management.
    > >>>
    > >>> In Jet you can only do it at the application level and this is high

    risk
    > >> by
    > >>> comparison.
    > >>>
    > >>> In general as I said above you should avoid Data Redundancy and Data
    > >>> Interdependence but this cannot always be achieved and still maintain

    a
    > >>> business system.
    > >>>
    > >>> OLAP is a case in point, it is by its very nature storing redundant

    data
    > >> but
    > >>> it is managed by the DBMS.
    > >>>
    > >>>
    > >>> --
    > >>> Slainte
    > >>>
    > >>> Craig Alexander Morrison
    > >>> Crawbridge Data (Scotland) Limited
    > >>> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >>> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > >>> > Expand and explain please as you appear to be wrong.
    > >>> >
    > >>> > --
    > >>> >
    > >>> > Terry Kreft
    > >>> >
    > >>> >
    > >>> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    wrote
    > >> in
    > >>> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > >>> >> It also relies on the data redundancy being managed by the database
    > >>> >> and
    > >>> > not
    > >>> >> the application(s).
    > >>> >>
    > >>> >> Jet in this regard is of no use and one should be using DB2, Oracle
    > >>> >> or
    > >>> >> SQL
    > >>> >> Server.
    > >>> >>
    > >>> >> --
    > >>> >> Slainte
    > >>> >>
    > >>> >> Craig Alexander Morrison
    > >>> >> Crawbridge Data (Scotland) Limited
    > >>> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >>> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > >>> >> > No, you have to code for it.
    > >>> >> >
    > >>> >> > The problem with denormalised data is maintaining integrity, this
    > >>> >> > relies
    > >>> >> > on
    > >>> >> > competent programming.
    > >>> >> >
    > >>> >> >
    > >>> >> > --
    > >>> >> >
    > >>> >> > Terry Kreft
    > >>> >> >
    > >>> >> >
    > >>> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    > >>> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >>> >> >> Is there a way to maintain real Referential Integrity of

    Redundant
    > >>> >> >> fields in two tables?
    > >>> >> >>
    > >>> >> >> I have searched the newsgroup and it seems the general advice is
    > >>> >> >> to
    > >>> >> >> not
    > >>> >> >> have redundant data at all. But sometimes space is less a

    concern
    > >> than
    > >>> >> >> computing power, so not having to join tables all the time to

    view
    > >>> >> >> data
    > >>> >> >> is preffered.
    > >>> >> >>
    > >>> >> >> Any comment is appreciated. Thank you.
    > >>> >> >>
    > >>> >> >> -Sam
    > >>> >> >>
    > >>> >> >
    > >>> >> >
    > >>> >>
    > >>> >>
    > >>> >
    > >>> >
    > >>>
    > >>>
    > >>
    > >>

    > >
    > >

    >
    >
     
  16. Craig Alexander Morrison

    Craig Alexander Morrison
    Expand Collapse
    Guest

    I understand now, and you would appear to be wrong.

    --
    Slainte

    Craig Alexander Morrison
    Crawbridge Data (Scotland) Limited
    "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    news:%23QqKl0PmGHA.4268@TK2MSFTNGP05.phx.gbl...
    >
    > Triggers are specialised SPROCS they do not form part of the inbuilt DRI,
    > that's why I say you're wrong. They _are_ part of the application
    >
    >
    > --
    >
    > Terry Kreft
    >
    >
    > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    > message news:OQS9zSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    >> I may be Scottish but I am watching England in the World Cup and after

    > that
    >> the Formula One Grand Prix of Canada.
    >>
    >> ...I would love to know why Terry thinks I am wrong, I would

    > wholeheartedly
    >> agree I was wrong if I was using Jet and then expecting Access at the
    >> application level to manage the redundancy.
    >>
    >> I use DB2 as the backend and therefore all necessary redundancy is

    > strictly
    >> managed as you say via Triggers and Triggered Actions.
    >>
    >> To quote from Chris Date "Incidentally, we do not mean to suggest that
    >> all
    >> redundancy can or necessarily should be eliminated...However, we do mean

    > to
    >> suggest that any such redundancy should be carefully controlled-that is

    > the
    >> DBMS should be aware of it, if it exists and should assume responsibility
    >> for "propagating updates"."
    >>
    >> --
    >> Slainte
    >>
    >> Craig Alexander Morrison
    >> Crawbridge Data (Scotland) Limited
    >>
    >> "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message
    >> news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    >> > I'm guessing, Terry, that Craig's talking about using triggers to
    >> > manage
    >> > the redundant data. However, it would be nice if he answered.
    >> >
    >> > --
    >> > Doug Steele, Microsoft Access MVP
    >> > http://I.Am/DougSteele
    >> > (no private e-mails, please)
    >> >
    >> >
    >> > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> > news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    >> >> I'm not sure what you mean by "Only the larger DBMSs can perform this
    >> >> management." could you expand on that please.
    >> >>
    >> >>
    >> >> --
    >> >>
    >> >> Terry Kreft
    >> >>
    >> >>
    >> >> "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    > in
    >> >> message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    >> >>> How do you manage data redundancy in Jet?
    >> >>>
    >> >>> Remember Data Redundancy should be avoided, if it cannot it needs to

    > be
    >> >>> managed by the DBMS.
    >> >>>
    >> >>> Only the larger DBMSs can perform this management.
    >> >>>
    >> >>> In Jet you can only do it at the application level and this is high

    > risk
    >> >> by
    >> >>> comparison.
    >> >>>
    >> >>> In general as I said above you should avoid Data Redundancy and Data
    >> >>> Interdependence but this cannot always be achieved and still maintain

    > a
    >> >>> business system.
    >> >>>
    >> >>> OLAP is a case in point, it is by its very nature storing redundant

    > data
    >> >> but
    >> >>> it is managed by the DBMS.
    >> >>>
    >> >>>
    >> >>> --
    >> >>> Slainte
    >> >>>
    >> >>> Craig Alexander Morrison
    >> >>> Crawbridge Data (Scotland) Limited
    >> >>> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >>> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    >> >>> > Expand and explain please as you appear to be wrong.
    >> >>> >
    >> >>> > --
    >> >>> >
    >> >>> > Terry Kreft
    >> >>> >
    >> >>> >
    >> >>> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > wrote
    >> >> in
    >> >>> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    >> >>> >> It also relies on the data redundancy being managed by the
    >> >>> >> database
    >> >>> >> and
    >> >>> > not
    >> >>> >> the application(s).
    >> >>> >>
    >> >>> >> Jet in this regard is of no use and one should be using DB2,
    >> >>> >> Oracle
    >> >>> >> or
    >> >>> >> SQL
    >> >>> >> Server.
    >> >>> >>
    >> >>> >> --
    >> >>> >> Slainte
    >> >>> >>
    >> >>> >> Craig Alexander Morrison
    >> >>> >> Crawbridge Data (Scotland) Limited
    >> >>> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >>> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    >> >>> >> > No, you have to code for it.
    >> >>> >> >
    >> >>> >> > The problem with denormalised data is maintaining integrity,
    >> >>> >> > this
    >> >>> >> > relies
    >> >>> >> > on
    >> >>> >> > competent programming.
    >> >>> >> >
    >> >>> >> >
    >> >>> >> > --
    >> >>> >> >
    >> >>> >> > Terry Kreft
    >> >>> >> >
    >> >>> >> >
    >> >>> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    >> >>> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >> >>> >> >> Is there a way to maintain real Referential Integrity of

    > Redundant
    >> >>> >> >> fields in two tables?
    >> >>> >> >>
    >> >>> >> >> I have searched the newsgroup and it seems the general advice
    >> >>> >> >> is
    >> >>> >> >> to
    >> >>> >> >> not
    >> >>> >> >> have redundant data at all. But sometimes space is less a

    > concern
    >> >> than
    >> >>> >> >> computing power, so not having to join tables all the time to

    > view
    >> >>> >> >> data
    >> >>> >> >> is preffered.
    >> >>> >> >>
    >> >>> >> >> Any comment is appreciated. Thank you.
    >> >>> >> >>
    >> >>> >> >> -Sam
    >> >>> >> >>
    >> >>> >> >
    >> >>> >> >
    >> >>> >>
    >> >>> >>
    >> >>> >
    >> >>> >
    >> >>>
    >> >>>
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >
     
  17. Craig Alexander Morrison

    Craig Alexander Morrison
    Expand Collapse
    Guest

    > The rest of your post seems to involve a fantasy conversation or a
    > conversation with someone other than myself.


    Sent to Doug when he stated it would be nice if I answered.

    Did you actually read my post or are you so positive that you are right and
    I am wrong.

    --
    Slainte

    Craig Alexander Morrison
    Crawbridge Data (Scotland) Limited
    "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    news:uS9MMzPmGHA.4700@TK2MSFTNGP02.phx.gbl...
    > Well, you're obviously not going to actually say why you said what you did
    > so I'll go along with my assumption.
    >
    > The reason why I believe that what you said was essentially wrong is that
    > I
    > believe you are referring to using triggers to maintain RI between
    > redundant
    > data in tables.
    >
    > My reasoning goes like this:-
    > Stored procedures are not part of the inbuilt DRI of the database
    > Triggers are only a special sort of SPROC therefore they are not part
    > of
    > the inbuilt DRI of the database.
    >
    > To put it another way triggers have to be coded, they are a developed item
    > and are part of the application rather than the dbms.
    >
    >
    > --
    >
    > Terry Kreft
    >
    >
    > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    > message news:OjcvpSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    >> No, I do not think so.
    >>
    >> But tell me what exactly you think I am wrong about as you did not
    >> address
    >> the question
    >>
    >> >> >> How do you manage data redundancy in Jet?

    >>
    >> You indicated to the OP that they could do "it" in code, however that

    > could
    >> only be at application level and this is easily subverted.
    >>
    >> Or are you actually saying that I should calculate the balances of 10
    >> million bank accounts to arrive at the customer deposits total in order
    >> to
    >> have a pure relational database with no redundant data.
    >>
    >> You know I always try to start with a pure design so that I know what
    >> redundancy we need to manage.
    >>
    >> BTW If you are using Jet then I would strongly recommend that you stay

    > with
    >> the "pure" design.
    >>
    >> --
    >> Slainte
    >>
    >> Craig Alexander Morrison
    >> Crawbridge Data (Scotland) Limited
    >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> news:OCXRxxFmGHA.3732@TK2MSFTNGP05.phx.gbl...
    >> > Hi Doug,
    >> >
    >> > Yep, That's exactly what I thought he was talking about and if so, was

    > the
    >> > reason why I was going to say that essentially he was wrong.
    >> >
    >> >
    >> >
    >> >
    >> > --
    >> >
    >> > Terry Kreft
    >> >
    >> >
    >> > "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in
    >> > message
    >> > news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    >> >> I'm guessing, Terry, that Craig's talking about using triggers to

    > manage
    >> > the
    >> >> redundant data. However, it would be nice if he answered.
    >> >>
    >> >> --
    >> >> Doug Steele, Microsoft Access MVP
    >> >> http://I.Am/DougSteele
    >> >> (no private e-mails, please)
    >> >>
    >> >>
    >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >> news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    >> >> > I'm not sure what you mean by "Only the larger DBMSs can perform
    >> >> > this
    >> >> > management." could you expand on that please.
    >> >> >
    >> >> >
    >> >> > --
    >> >> >
    >> >> > Terry Kreft
    >> >> >
    >> >> >
    >> >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > wrote
    >> > in
    >> >> > message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    >> >> >> How do you manage data redundancy in Jet?
    >> >> >>
    >> >> >> Remember Data Redundancy should be avoided, if it cannot it needs
    >> >> >> to
    >> >> >> be
    >> >> >> managed by the DBMS.
    >> >> >>
    >> >> >> Only the larger DBMSs can perform this management.
    >> >> >>
    >> >> >> In Jet you can only do it at the application level and this is high
    >> > risk
    >> >> > by
    >> >> >> comparison.
    >> >> >>
    >> >> >> In general as I said above you should avoid Data Redundancy and
    >> >> >> Data
    >> >> >> Interdependence but this cannot always be achieved and still

    > maintain
    >> >> >> a
    >> >> >> business system.
    >> >> >>
    >> >> >> OLAP is a case in point, it is by its very nature storing redundant
    >> > data
    >> >> > but
    >> >> >> it is managed by the DBMS.
    >> >> >>
    >> >> >>
    >> >> >> --
    >> >> >> Slainte
    >> >> >>
    >> >> >> Craig Alexander Morrison
    >> >> >> Crawbridge Data (Scotland) Limited
    >> >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >> >> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    >> >> >> > Expand and explain please as you appear to be wrong.
    >> >> >> >
    >> >> >> > --
    >> >> >> >
    >> >> >> > Terry Kreft
    >> >> >> >
    >> >> >> >
    >> >> >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>
    >> > wrote
    >> >> > in
    >> >> >> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    >> >> >> >> It also relies on the data redundancy being managed by the

    > database
    >> >> >> >> and
    >> >> >> > not
    >> >> >> >> the application(s).
    >> >> >> >>
    >> >> >> >> Jet in this regard is of no use and one should be using DB2,

    > Oracle
    >> > or
    >> >> >> >> SQL
    >> >> >> >> Server.
    >> >> >> >>
    >> >> >> >> --
    >> >> >> >> Slainte
    >> >> >> >>
    >> >> >> >> Craig Alexander Morrison
    >> >> >> >> Crawbridge Data (Scotland) Limited
    >> >> >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >> >> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    >> >> >> >> > No, you have to code for it.
    >> >> >> >> >
    >> >> >> >> > The problem with denormalised data is maintaining integrity,

    > this
    >> >> >> >> > relies
    >> >> >> >> > on
    >> >> >> >> > competent programming.
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >> > --
    >> >> >> >> >
    >> >> >> >> > Terry Kreft
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    >> >> >> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >> >> >> >> >> Is there a way to maintain real Referential Integrity of
    >> > Redundant
    >> >> >> >> >> fields in two tables?
    >> >> >> >> >>
    >> >> >> >> >> I have searched the newsgroup and it seems the general advice

    > is
    >> > to
    >> >> >> >> >> not
    >> >> >> >> >> have redundant data at all. But sometimes space is less a
    >> >> >> >> >> concern
    >> >> > than
    >> >> >> >> >> computing power, so not having to join tables all the time to
    >> > view
    >> >> >> >> >> data
    >> >> >> >> >> is preffered.
    >> >> >> >> >>
    >> >> >> >> >> Any comment is appreciated. Thank you.
    >> >> >> >> >>
    >> >> >> >> >> -Sam
    >> >> >> >> >>
    >> >> >> >> >
    >> >> >> >> >
    >> >> >> >>
    >> >> >> >>
    >> >> >> >
    >> >> >> >
    >> >> >>
    >> >> >>
    >> >> >
    >> >> >
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >
     
  18. Craig Alexander Morrison

    Craig Alexander Morrison
    Expand Collapse
    Guest

    Excerpt from my message to Doug

    To quote from Chris Date "Incidentally, we do not mean to suggest that all
    redundancy can or necessarily should be eliminated...However, we do mean to
    suggest that any such redundancy should be carefully controlled-that is the
    DBMS should be aware of it, if it exists and should assume responsibility
    for "propagating updates"."



    --
    Slainte

    Craig Alexander Morrison
    Crawbridge Data (Scotland) Limited
    "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    news:%23QqKl0PmGHA.4268@TK2MSFTNGP05.phx.gbl...
    >
    > Triggers are specialised SPROCS they do not form part of the inbuilt DRI,
    > that's why I say you're wrong. They _are_ part of the application
    >
    >
    > --
    >
    > Terry Kreft
    >
    >
    > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    > message news:OQS9zSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    >> I may be Scottish but I am watching England in the World Cup and after

    > that
    >> the Formula One Grand Prix of Canada.
    >>
    >> ...I would love to know why Terry thinks I am wrong, I would

    > wholeheartedly
    >> agree I was wrong if I was using Jet and then expecting Access at the
    >> application level to manage the redundancy.
    >>
    >> I use DB2 as the backend and therefore all necessary redundancy is

    > strictly
    >> managed as you say via Triggers and Triggered Actions.
    >>
    >> To quote from Chris Date "Incidentally, we do not mean to suggest that
    >> all
    >> redundancy can or necessarily should be eliminated...However, we do mean

    > to
    >> suggest that any such redundancy should be carefully controlled-that is

    > the
    >> DBMS should be aware of it, if it exists and should assume responsibility
    >> for "propagating updates"."
    >>
    >> --
    >> Slainte
    >>
    >> Craig Alexander Morrison
    >> Crawbridge Data (Scotland) Limited
    >>
    >> "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message
    >> news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    >> > I'm guessing, Terry, that Craig's talking about using triggers to
    >> > manage
    >> > the redundant data. However, it would be nice if he answered.
    >> >
    >> > --
    >> > Doug Steele, Microsoft Access MVP
    >> > http://I.Am/DougSteele
    >> > (no private e-mails, please)
    >> >
    >> >
    >> > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> > news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    >> >> I'm not sure what you mean by "Only the larger DBMSs can perform this
    >> >> management." could you expand on that please.
    >> >>
    >> >>
    >> >> --
    >> >>
    >> >> Terry Kreft
    >> >>
    >> >>
    >> >> "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    > in
    >> >> message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    >> >>> How do you manage data redundancy in Jet?
    >> >>>
    >> >>> Remember Data Redundancy should be avoided, if it cannot it needs to

    > be
    >> >>> managed by the DBMS.
    >> >>>
    >> >>> Only the larger DBMSs can perform this management.
    >> >>>
    >> >>> In Jet you can only do it at the application level and this is high

    > risk
    >> >> by
    >> >>> comparison.
    >> >>>
    >> >>> In general as I said above you should avoid Data Redundancy and Data
    >> >>> Interdependence but this cannot always be achieved and still maintain

    > a
    >> >>> business system.
    >> >>>
    >> >>> OLAP is a case in point, it is by its very nature storing redundant

    > data
    >> >> but
    >> >>> it is managed by the DBMS.
    >> >>>
    >> >>>
    >> >>> --
    >> >>> Slainte
    >> >>>
    >> >>> Craig Alexander Morrison
    >> >>> Crawbridge Data (Scotland) Limited
    >> >>> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >>> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    >> >>> > Expand and explain please as you appear to be wrong.
    >> >>> >
    >> >>> > --
    >> >>> >
    >> >>> > Terry Kreft
    >> >>> >
    >> >>> >
    >> >>> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > wrote
    >> >> in
    >> >>> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    >> >>> >> It also relies on the data redundancy being managed by the
    >> >>> >> database
    >> >>> >> and
    >> >>> > not
    >> >>> >> the application(s).
    >> >>> >>
    >> >>> >> Jet in this regard is of no use and one should be using DB2,
    >> >>> >> Oracle
    >> >>> >> or
    >> >>> >> SQL
    >> >>> >> Server.
    >> >>> >>
    >> >>> >> --
    >> >>> >> Slainte
    >> >>> >>
    >> >>> >> Craig Alexander Morrison
    >> >>> >> Crawbridge Data (Scotland) Limited
    >> >>> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    >> >>> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    >> >>> >> > No, you have to code for it.
    >> >>> >> >
    >> >>> >> > The problem with denormalised data is maintaining integrity,
    >> >>> >> > this
    >> >>> >> > relies
    >> >>> >> > on
    >> >>> >> > competent programming.
    >> >>> >> >
    >> >>> >> >
    >> >>> >> > --
    >> >>> >> >
    >> >>> >> > Terry Kreft
    >> >>> >> >
    >> >>> >> >
    >> >>> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    >> >>> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    >> >>> >> >> Is there a way to maintain real Referential Integrity of

    > Redundant
    >> >>> >> >> fields in two tables?
    >> >>> >> >>
    >> >>> >> >> I have searched the newsgroup and it seems the general advice
    >> >>> >> >> is
    >> >>> >> >> to
    >> >>> >> >> not
    >> >>> >> >> have redundant data at all. But sometimes space is less a

    > concern
    >> >> than
    >> >>> >> >> computing power, so not having to join tables all the time to

    > view
    >> >>> >> >> data
    >> >>> >> >> is preffered.
    >> >>> >> >>
    >> >>> >> >> Any comment is appreciated. Thank you.
    >> >>> >> >>
    >> >>> >> >> -Sam
    >> >>> >> >>
    >> >>> >> >
    >> >>> >> >
    >> >>> >>
    >> >>> >>
    >> >>> >
    >> >>> >
    >> >>>
    >> >>>
    >> >>
    >> >>
    >> >
    >> >

    >>
    >>

    >
    >
     
  19. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    You responded to my response to Doug.

    Did you actually read this thread or are you still confused?

    --

    Terry Kreft


    "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    message news:ui8Yc$PmGHA.5076@TK2MSFTNGP02.phx.gbl...
    > > The rest of your post seems to involve a fantasy conversation or a
    > > conversation with someone other than myself.

    >
    > Sent to Doug when he stated it would be nice if I answered.
    >
    > Did you actually read my post or are you so positive that you are right

    and
    > I am wrong.
    >
    > --
    > Slainte
    >
    > Craig Alexander Morrison
    > Crawbridge Data (Scotland) Limited
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:uS9MMzPmGHA.4700@TK2MSFTNGP02.phx.gbl...
    > > Well, you're obviously not going to actually say why you said what you

    did
    > > so I'll go along with my assumption.
    > >
    > > The reason why I believe that what you said was essentially wrong is

    that
    > > I
    > > believe you are referring to using triggers to maintain RI between
    > > redundant
    > > data in tables.
    > >
    > > My reasoning goes like this:-
    > > Stored procedures are not part of the inbuilt DRI of the database
    > > Triggers are only a special sort of SPROC therefore they are not part
    > > of
    > > the inbuilt DRI of the database.
    > >
    > > To put it another way triggers have to be coded, they are a developed

    item
    > > and are part of the application rather than the dbms.
    > >
    > >
    > > --
    > >
    > > Terry Kreft
    > >
    > >
    > > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    in
    > > message news:OjcvpSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    > >> No, I do not think so.
    > >>
    > >> But tell me what exactly you think I am wrong about as you did not
    > >> address
    > >> the question
    > >>
    > >> >> >> How do you manage data redundancy in Jet?
    > >>
    > >> You indicated to the OP that they could do "it" in code, however that

    > > could
    > >> only be at application level and this is easily subverted.
    > >>
    > >> Or are you actually saying that I should calculate the balances of 10
    > >> million bank accounts to arrive at the customer deposits total in order
    > >> to
    > >> have a pure relational database with no redundant data.
    > >>
    > >> You know I always try to start with a pure design so that I know what
    > >> redundancy we need to manage.
    > >>
    > >> BTW If you are using Jet then I would strongly recommend that you stay

    > > with
    > >> the "pure" design.
    > >>
    > >> --
    > >> Slainte
    > >>
    > >> Craig Alexander Morrison
    > >> Crawbridge Data (Scotland) Limited
    > >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> news:OCXRxxFmGHA.3732@TK2MSFTNGP05.phx.gbl...
    > >> > Hi Doug,
    > >> >
    > >> > Yep, That's exactly what I thought he was talking about and if so,

    was
    > > the
    > >> > reason why I was going to say that essentially he was wrong.
    > >> >
    > >> >
    > >> >
    > >> >
    > >> > --
    > >> >
    > >> > Terry Kreft
    > >> >
    > >> >
    > >> > "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in
    > >> > message
    > >> > news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    > >> >> I'm guessing, Terry, that Craig's talking about using triggers to

    > > manage
    > >> > the
    > >> >> redundant data. However, it would be nice if he answered.
    > >> >>
    > >> >> --
    > >> >> Doug Steele, Microsoft Access MVP
    > >> >> http://I.Am/DougSteele
    > >> >> (no private e-mails, please)
    > >> >>
    > >> >>
    > >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >> news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    > >> >> > I'm not sure what you mean by "Only the larger DBMSs can perform
    > >> >> > this
    > >> >> > management." could you expand on that please.
    > >> >> >
    > >> >> >
    > >> >> > --
    > >> >> >
    > >> >> > Terry Kreft
    > >> >> >
    > >> >> >
    > >> >> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > > wrote
    > >> > in
    > >> >> > message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    > >> >> >> How do you manage data redundancy in Jet?
    > >> >> >>
    > >> >> >> Remember Data Redundancy should be avoided, if it cannot it needs
    > >> >> >> to
    > >> >> >> be
    > >> >> >> managed by the DBMS.
    > >> >> >>
    > >> >> >> Only the larger DBMSs can perform this management.
    > >> >> >>
    > >> >> >> In Jet you can only do it at the application level and this is

    high
    > >> > risk
    > >> >> > by
    > >> >> >> comparison.
    > >> >> >>
    > >> >> >> In general as I said above you should avoid Data Redundancy and
    > >> >> >> Data
    > >> >> >> Interdependence but this cannot always be achieved and still

    > > maintain
    > >> >> >> a
    > >> >> >> business system.
    > >> >> >>
    > >> >> >> OLAP is a case in point, it is by its very nature storing

    redundant
    > >> > data
    > >> >> > but
    > >> >> >> it is managed by the DBMS.
    > >> >> >>
    > >> >> >>
    > >> >> >> --
    > >> >> >> Slainte
    > >> >> >>
    > >> >> >> Craig Alexander Morrison
    > >> >> >> Crawbridge Data (Scotland) Limited
    > >> >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >> >> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > >> >> >> > Expand and explain please as you appear to be wrong.
    > >> >> >> >
    > >> >> >> > --
    > >> >> >> >
    > >> >> >> > Terry Kreft
    > >> >> >> >
    > >> >> >> >
    > >> >> >> > "Craig Alexander Morrison"

    <cam@microsoft.newsgroups.public.com>
    > >> > wrote
    > >> >> > in
    > >> >> >> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > >> >> >> >> It also relies on the data redundancy being managed by the

    > > database
    > >> >> >> >> and
    > >> >> >> > not
    > >> >> >> >> the application(s).
    > >> >> >> >>
    > >> >> >> >> Jet in this regard is of no use and one should be using DB2,

    > > Oracle
    > >> > or
    > >> >> >> >> SQL
    > >> >> >> >> Server.
    > >> >> >> >>
    > >> >> >> >> --
    > >> >> >> >> Slainte
    > >> >> >> >>
    > >> >> >> >> Craig Alexander Morrison
    > >> >> >> >> Crawbridge Data (Scotland) Limited
    > >> >> >> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >> >> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > >> >> >> >> > No, you have to code for it.
    > >> >> >> >> >
    > >> >> >> >> > The problem with denormalised data is maintaining integrity,


    > > this
    > >> >> >> >> > relies
    > >> >> >> >> > on
    > >> >> >> >> > competent programming.
    > >> >> >> >> >
    > >> >> >> >> >
    > >> >> >> >> > --
    > >> >> >> >> >
    > >> >> >> >> > Terry Kreft
    > >> >> >> >> >
    > >> >> >> >> >
    > >> >> >> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    > >> >> >> >> >

    news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >> >> >> >> >> Is there a way to maintain real Referential Integrity of
    > >> > Redundant
    > >> >> >> >> >> fields in two tables?
    > >> >> >> >> >>
    > >> >> >> >> >> I have searched the newsgroup and it seems the general

    advice
    > > is
    > >> > to
    > >> >> >> >> >> not
    > >> >> >> >> >> have redundant data at all. But sometimes space is less a
    > >> >> >> >> >> concern
    > >> >> > than
    > >> >> >> >> >> computing power, so not having to join tables all the time

    to
    > >> > view
    > >> >> >> >> >> data
    > >> >> >> >> >> is preffered.
    > >> >> >> >> >>
    > >> >> >> >> >> Any comment is appreciated. Thank you.
    > >> >> >> >> >>
    > >> >> >> >> >> -Sam
    > >> >> >> >> >>
    > >> >> >> >> >
    > >> >> >> >> >
    > >> >> >> >>
    > >> >> >> >>
    > >> >> >> >
    > >> >> >> >
    > >> >> >>
    > >> >> >>
    > >> >> >
    > >> >> >
    > >> >>
    > >> >>
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >
     
  20. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    I fail to see the relevance of your response.


    --

    Terry Kreft


    "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    message news:%23wBBrAQmGHA.1596@TK2MSFTNGP04.phx.gbl...
    > Excerpt from my message to Doug
    >
    > To quote from Chris Date "Incidentally, we do not mean to suggest that all
    > redundancy can or necessarily should be eliminated...However, we do mean

    to
    > suggest that any such redundancy should be carefully controlled-that is

    the
    > DBMS should be aware of it, if it exists and should assume responsibility
    > for "propagating updates"."
    >
    >
    >
    > --
    > Slainte
    >
    > Craig Alexander Morrison
    > Crawbridge Data (Scotland) Limited
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:%23QqKl0PmGHA.4268@TK2MSFTNGP05.phx.gbl...
    > >
    > > Triggers are specialised SPROCS they do not form part of the inbuilt

    DRI,
    > > that's why I say you're wrong. They _are_ part of the application
    > >
    > >
    > > --
    > >
    > > Terry Kreft
    > >
    > >
    > > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    in
    > > message news:OQS9zSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    > >> I may be Scottish but I am watching England in the World Cup and after

    > > that
    > >> the Formula One Grand Prix of Canada.
    > >>
    > >> ...I would love to know why Terry thinks I am wrong, I would

    > > wholeheartedly
    > >> agree I was wrong if I was using Jet and then expecting Access at the
    > >> application level to manage the redundancy.
    > >>
    > >> I use DB2 as the backend and therefore all necessary redundancy is

    > > strictly
    > >> managed as you say via Triggers and Triggered Actions.
    > >>
    > >> To quote from Chris Date "Incidentally, we do not mean to suggest that
    > >> all
    > >> redundancy can or necessarily should be eliminated...However, we do

    mean
    > > to
    > >> suggest that any such redundancy should be carefully controlled-that is

    > > the
    > >> DBMS should be aware of it, if it exists and should assume

    responsibility
    > >> for "propagating updates"."
    > >>
    > >> --
    > >> Slainte
    > >>
    > >> Craig Alexander Morrison
    > >> Crawbridge Data (Scotland) Limited
    > >>
    > >> "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in

    message
    > >> news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    > >> > I'm guessing, Terry, that Craig's talking about using triggers to
    > >> > manage
    > >> > the redundant data. However, it would be nice if he answered.
    > >> >
    > >> > --
    > >> > Doug Steele, Microsoft Access MVP
    > >> > http://I.Am/DougSteele
    > >> > (no private e-mails, please)
    > >> >
    > >> >
    > >> > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> > news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    > >> >> I'm not sure what you mean by "Only the larger DBMSs can perform

    this
    > >> >> management." could you expand on that please.
    > >> >>
    > >> >>
    > >> >> --
    > >> >>
    > >> >> Terry Kreft
    > >> >>
    > >> >>
    > >> >> "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    wrote
    > > in
    > >> >> message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    > >> >>> How do you manage data redundancy in Jet?
    > >> >>>
    > >> >>> Remember Data Redundancy should be avoided, if it cannot it needs

    to
    > > be
    > >> >>> managed by the DBMS.
    > >> >>>
    > >> >>> Only the larger DBMSs can perform this management.
    > >> >>>
    > >> >>> In Jet you can only do it at the application level and this is high

    > > risk
    > >> >> by
    > >> >>> comparison.
    > >> >>>
    > >> >>> In general as I said above you should avoid Data Redundancy and

    Data
    > >> >>> Interdependence but this cannot always be achieved and still

    maintain
    > > a
    > >> >>> business system.
    > >> >>>
    > >> >>> OLAP is a case in point, it is by its very nature storing redundant

    > > data
    > >> >> but
    > >> >>> it is managed by the DBMS.
    > >> >>>
    > >> >>>
    > >> >>> --
    > >> >>> Slainte
    > >> >>>
    > >> >>> Craig Alexander Morrison
    > >> >>> Crawbridge Data (Scotland) Limited
    > >> >>> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >>> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > >> >>> > Expand and explain please as you appear to be wrong.
    > >> >>> >
    > >> >>> > --
    > >> >>> >
    > >> >>> > Terry Kreft
    > >> >>> >
    > >> >>> >
    > >> >>> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > > wrote
    > >> >> in
    > >> >>> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > >> >>> >> It also relies on the data redundancy being managed by the
    > >> >>> >> database
    > >> >>> >> and
    > >> >>> > not
    > >> >>> >> the application(s).
    > >> >>> >>
    > >> >>> >> Jet in this regard is of no use and one should be using DB2,
    > >> >>> >> Oracle
    > >> >>> >> or
    > >> >>> >> SQL
    > >> >>> >> Server.
    > >> >>> >>
    > >> >>> >> --
    > >> >>> >> Slainte
    > >> >>> >>
    > >> >>> >> Craig Alexander Morrison
    > >> >>> >> Crawbridge Data (Scotland) Limited
    > >> >>> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >>> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > >> >>> >> > No, you have to code for it.
    > >> >>> >> >
    > >> >>> >> > The problem with denormalised data is maintaining integrity,
    > >> >>> >> > this
    > >> >>> >> > relies
    > >> >>> >> > on
    > >> >>> >> > competent programming.
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >> > --
    > >> >>> >> >
    > >> >>> >> > Terry Kreft
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    > >> >>> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >> >>> >> >> Is there a way to maintain real Referential Integrity of

    > > Redundant
    > >> >>> >> >> fields in two tables?
    > >> >>> >> >>
    > >> >>> >> >> I have searched the newsgroup and it seems the general advice
    > >> >>> >> >> is
    > >> >>> >> >> to
    > >> >>> >> >> not
    > >> >>> >> >> have redundant data at all. But sometimes space is less a

    > > concern
    > >> >> than
    > >> >>> >> >> computing power, so not having to join tables all the time to

    > > view
    > >> >>> >> >> data
    > >> >>> >> >> is preffered.
    > >> >>> >> >>
    > >> >>> >> >> Any comment is appreciated. Thank you.
    > >> >>> >> >>
    > >> >>> >> >> -Sam
    > >> >>> >> >>
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >>
    > >> >>> >>
    > >> >>> >
    > >> >>> >
    > >> >>>
    > >> >>>
    > >> >>
    > >> >>
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >
     
  21. Terry Kreft

    Terry Kreft
    Expand Collapse
    Guest

    Patently, appearances can be deceptive.

    --

    Terry Kreft


    "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote in
    message news:%23%234$b%23PmGHA.748@TK2MSFTNGP02.phx.gbl...
    > I understand now, and you would appear to be wrong.
    >
    > --
    > Slainte
    >
    > Craig Alexander Morrison
    > Crawbridge Data (Scotland) Limited
    > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > news:%23QqKl0PmGHA.4268@TK2MSFTNGP05.phx.gbl...
    > >
    > > Triggers are specialised SPROCS they do not form part of the inbuilt

    DRI,
    > > that's why I say you're wrong. They _are_ part of the application
    > >
    > >
    > > --
    > >
    > > Terry Kreft
    > >
    > >
    > > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com> wrote

    in
    > > message news:OQS9zSPmGHA.3880@TK2MSFTNGP02.phx.gbl...
    > >> I may be Scottish but I am watching England in the World Cup and after

    > > that
    > >> the Formula One Grand Prix of Canada.
    > >>
    > >> ...I would love to know why Terry thinks I am wrong, I would

    > > wholeheartedly
    > >> agree I was wrong if I was using Jet and then expecting Access at the
    > >> application level to manage the redundancy.
    > >>
    > >> I use DB2 as the backend and therefore all necessary redundancy is

    > > strictly
    > >> managed as you say via Triggers and Triggered Actions.
    > >>
    > >> To quote from Chris Date "Incidentally, we do not mean to suggest that
    > >> all
    > >> redundancy can or necessarily should be eliminated...However, we do

    mean
    > > to
    > >> suggest that any such redundancy should be carefully controlled-that is

    > > the
    > >> DBMS should be aware of it, if it exists and should assume

    responsibility
    > >> for "propagating updates"."
    > >>
    > >> --
    > >> Slainte
    > >>
    > >> Craig Alexander Morrison
    > >> Crawbridge Data (Scotland) Limited
    > >>
    > >> "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in

    message
    > >> news:e31HtWEmGHA.3752@TK2MSFTNGP02.phx.gbl...
    > >> > I'm guessing, Terry, that Craig's talking about using triggers to
    > >> > manage
    > >> > the redundant data. However, it would be nice if he answered.
    > >> >
    > >> > --
    > >> > Doug Steele, Microsoft Access MVP
    > >> > http://I.Am/DougSteele
    > >> > (no private e-mails, please)
    > >> >
    > >> >
    > >> > "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> > news:uyQswREmGHA.4164@TK2MSFTNGP03.phx.gbl...
    > >> >> I'm not sure what you mean by "Only the larger DBMSs can perform

    this
    > >> >> management." could you expand on that please.
    > >> >>
    > >> >>
    > >> >> --
    > >> >>
    > >> >> Terry Kreft
    > >> >>
    > >> >>
    > >> >> "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    wrote
    > > in
    > >> >> message news:%235k61J8lGHA.748@TK2MSFTNGP02.phx.gbl...
    > >> >>> How do you manage data redundancy in Jet?
    > >> >>>
    > >> >>> Remember Data Redundancy should be avoided, if it cannot it needs

    to
    > > be
    > >> >>> managed by the DBMS.
    > >> >>>
    > >> >>> Only the larger DBMSs can perform this management.
    > >> >>>
    > >> >>> In Jet you can only do it at the application level and this is high

    > > risk
    > >> >> by
    > >> >>> comparison.
    > >> >>>
    > >> >>> In general as I said above you should avoid Data Redundancy and

    Data
    > >> >>> Interdependence but this cannot always be achieved and still

    maintain
    > > a
    > >> >>> business system.
    > >> >>>
    > >> >>> OLAP is a case in point, it is by its very nature storing redundant

    > > data
    > >> >> but
    > >> >>> it is managed by the DBMS.
    > >> >>>
    > >> >>>
    > >> >>> --
    > >> >>> Slainte
    > >> >>>
    > >> >>> Craig Alexander Morrison
    > >> >>> Crawbridge Data (Scotland) Limited
    > >> >>> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >>> news:eI7jgo7lGHA.4596@TK2MSFTNGP05.phx.gbl...
    > >> >>> > Expand and explain please as you appear to be wrong.
    > >> >>> >
    > >> >>> > --
    > >> >>> >
    > >> >>> > Terry Kreft
    > >> >>> >
    > >> >>> >
    > >> >>> > "Craig Alexander Morrison" <cam@microsoft.newsgroups.public.com>

    > > wrote
    > >> >> in
    > >> >>> > message news:uWRBgN6lGHA.4864@TK2MSFTNGP04.phx.gbl...
    > >> >>> >> It also relies on the data redundancy being managed by the
    > >> >>> >> database
    > >> >>> >> and
    > >> >>> > not
    > >> >>> >> the application(s).
    > >> >>> >>
    > >> >>> >> Jet in this regard is of no use and one should be using DB2,
    > >> >>> >> Oracle
    > >> >>> >> or
    > >> >>> >> SQL
    > >> >>> >> Server.
    > >> >>> >>
    > >> >>> >> --
    > >> >>> >> Slainte
    > >> >>> >>
    > >> >>> >> Craig Alexander Morrison
    > >> >>> >> Crawbridge Data (Scotland) Limited
    > >> >>> >> "Terry Kreft" <terry.kreft@mps.co.uk> wrote in message
    > >> >>> >> news:uCKMlG2lGHA.2180@TK2MSFTNGP05.phx.gbl...
    > >> >>> >> > No, you have to code for it.
    > >> >>> >> >
    > >> >>> >> > The problem with denormalised data is maintaining integrity,
    > >> >>> >> > this
    > >> >>> >> > relies
    > >> >>> >> > on
    > >> >>> >> > competent programming.
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >> > --
    > >> >>> >> >
    > >> >>> >> > Terry Kreft
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >> > "Sam" <sampahkertas@yahoo.com> wrote in message
    > >> >>> >> > news:1151130985.518500.136120@p79g2000cwp.googlegroups.com...
    > >> >>> >> >> Is there a way to maintain real Referential Integrity of

    > > Redundant
    > >> >>> >> >> fields in two tables?
    > >> >>> >> >>
    > >> >>> >> >> I have searched the newsgroup and it seems the general advice
    > >> >>> >> >> is
    > >> >>> >> >> to
    > >> >>> >> >> not
    > >> >>> >> >> have redundant data at all. But sometimes space is less a

    > > concern
    > >> >> than
    > >> >>> >> >> computing power, so not having to join tables all the time to

    > > view
    > >> >>> >> >> data
    > >> >>> >> >> is preffered.
    > >> >>> >> >>
    > >> >>> >> >> Any comment is appreciated. Thank you.
    > >> >>> >> >>
    > >> >>> >> >> -Sam
    > >> >>> >> >>
    > >> >>> >> >
    > >> >>> >> >
    > >> >>> >>
    > >> >>> >>
    > >> >>> >
    > >> >>> >
    > >> >>>
    > >> >>>
    > >> >>
    > >> >>
    > >> >
    > >> >
    > >>
    > >>

    > >
    > >

    >
    >
     

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