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an Access DBMS with NO RELATIONSHIPS?

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

  1. kt

    kt
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    Guest

    Hi
    In looking at a database within my new employer and have noticed that there
    are no relationships set up. Some of the tables are linked from external
    databases and many are created ad-hoc by various novice users.
    I have been asked to build reports based on the data in this database - I am
    leary as there are no relationships - leading me to believe the data does not
    have referential integrity and is not reliable.
    Does anyone know if my fear is irrational since many (but not all) of the
    table are linked from an external source (probably star schema warehouse)?
    --
    kt
     
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  3. Guest

    Guest
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    Guest

    In Access, it is not possible to use Declarative Referential Integrity
    on external data. DRI only applies to MDB tables in one MDB
    database.

    In Access, you won't be able to see relationships defined in a
    data warehouse.

    In Access, you can declare relationships between external tables,
    or between external and internal tables, but those relationships
    are meaningless - they are only helpful as guidelines when building
    queries.

    Access is a good platform for building reports based on external
    data.

    The quality of the external data is up to you: Access can't help
    you there.

    (david)


    "kt" <kt@discussions.microsoft.com> wrote in message
    news:1C92F2F5-46CB-473B-8359-50F1C6D98431@microsoft.com...
    > Hi
    > In looking at a database within my new employer and have noticed that

    there
    > are no relationships set up. Some of the tables are linked from external
    > databases and many are created ad-hoc by various novice users.
    > I have been asked to build reports based on the data in this database - I

    am
    > leary as there are no relationships - leading me to believe the data does

    not
    > have referential integrity and is not reliable.
    > Does anyone know if my fear is irrational since many (but not all) of the
    > table are linked from an external source (probably star schema warehouse)?
    > --
    > kt
     
  4. John Vinson

    John Vinson
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    Guest

    On Mon, 8 May 2006 16:11:02 -0700, kt <kt@discussions.microsoft.com>
    wrote:

    >Hi
    >In looking at a database within my new employer and have noticed that there
    >are no relationships set up. Some of the tables are linked from external
    >databases and many are created ad-hoc by various novice users.
    >I have been asked to build reports based on the data in this database - I am
    >leary as there are no relationships - leading me to believe the data does not
    >have referential integrity and is not reliable.
    >Does anyone know if my fear is irrational since many (but not all) of the
    >table are linked from an external source (probably star schema warehouse)?


    You cannot establish relationships with RI enforced to linked tables
    in any case... but you're quite right, unless the relationships are
    enforced *somewhere* (in the data warehouse, in the code which
    extracts the data, or other) then the Garbage In - Garbage Out
    phenomenon will certainly rear its ugly head.

    You might want to do some testing - try the Unmatched Query wizard on
    some pairs of tables which should logically be related, to see if
    there are "orphan" records. I'd be rather surprised if there are not.

    John W. Vinson[MVP]
     

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