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DB Design - Microsoft SQL / MS SQL Server

I have had an argument with a technician DB who has planned a table SQL without include domain and referential integrity declaratory rule and with a column without identity. The meaning of this column is explained by another column on the same table. I have explain that such solution is in contrast with rules 1 and 10 of Codd that say: 1 - Information rule Given to are represented only one way: as values within columns within rows. Simple, consistent and poured them. The basic requirement of the relational model. 10 - Integrity independence Integrity constraints to are to be ...

  1. #1

    Default DB Design

    I have had an argument with a technician DB who has
    planned a table SQL without include domain and referential
    integrity declaratory rule and with a column without
    identity. The meaning of this column is explained by
    another column on the same table. I have explain that
    such solution is in contrast with rules 1 and 10 of Codd
    that say:
    1 - Information rule Given to are represented only one
    way: as values within columns within rows. Simple,
    consistent and poured them. The basic requirement of the
    relational model.
    10 - Integrity independence Integrity constraints to are
    to be stored in the catalog not the programs. Alterations
    to integrity constraints should not affect application
    programs. This simplifies the programs. It is not always
    possible to I give this.

    The technician affirm that the Codd's rules do not regard
    the design of the DB, but only the RDBMS
    implementations. In other words, they do not regard the
    structure of db that it comes constructed to the inside of
    a RDBMS Oracle or SQLServer, but just which are the
    minimal conditions that Oracle and SQLServer must
    implement for being able themselves to declare systems of
    management of database relational.
    Therefore the rule does not have null to that seeing with
    the eventual techniques of design of the db in how much it
    regards only the suppliers of the RDBMS, and cannot be
    thought binding in the choice, as an example, of the
    modalities of management of the columns of one table.
    In practical, the design of a table can be corrected even
    if in contrast with all the rules of Codd. To my
    observation that in this way integrity of gives to you way
    does not come in guaranteed al, the technician supports
    that the eventuality of a incoherent update will have to
    be the application to carry out the controls considering,
    through utility whichever, ago part of the normal risks.
    Personally I consider such absolutely dangerous
    affirmations, but I would wish to feel other opinions.

    Riccardo Guest

  2. #2

    Default Re: DB Design

    RI and validation should always be done in the database. If not, how can you
    be sure that every application enforces all the same rules? What happens
    when the rules change? Do you update every application at once?

    Also, your data has value in itself, independently of the originating
    application. Decision support and similar ytics are extremely difficult,
    and maybe impossible, if the data has no built-in integrity.

    --
    David Portas
    ------------
    Please reply only to the newsgroup
    --


    David Guest

  3. #3

    Default Re: DB Design

    >> technician DB who has planned a table SQL without include domain and
    referential integrity declaratory rule and with a column without
    identity. <<

    Yes, this man is dangerous.

    The IDENTITY is a non-relational, proprietary thing that you should not
    use, but without any domain or DRI rules, you cannot have a consistent
    logical model.
     [/ref]
    table. <<

    So when column #2 is wrong, it also destroys column #1. Unless you had
    complex constraints on the domains, which he does not want to have.

    Codd's rules are to maintain data integrity, and that needs to be part
    of the design of the database.

    --CELKO--
    ===========================
    Please post DDL, so that people do not have to guess what the keys,
    constraints, Declarative Referential Integrity, datatypes, etc. in your
    schema are.

    *** Sent via Developersdex http://www.developersdex.com ***
    Don't just participate in USENET...get rewarded for it!
    Joe Guest

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