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Thread: Urgent! Advice needed on resolving Many-To-Many Relationships

  1. #1
    Join Date
    Oct 2007
    Posts
    15

    Urgent! Advice needed on resolving Many-To-Many Relationships

    I have a fact table where a single record may have multiple permutations of a single attribute so I need some advice as to how I may go about handling the relationships of these attributes to their appropriate dimension.

    As an example, a person may have a single record in the fact table but may list up to 5 different States in that record which go back to a State Dimension.

    What is the best approach to associate those 5 States for that 1 individual to the State dimension?

    So this isn't a true many to many relationship in the sense that the same individual isn't listed 5 times in the fact table for each State. But rather that the 1 individual is listed in the fact table but may list many States in the single record.

    If more clarification of the problem is required, please let me know but I believe the issue is pretty straight forward as I've explained.

    Thanks much for any advice whatsoever!

  2. #2
    Join Date
    Sep 2002
    Posts
    5,938
    Usually can set two one to many relationships for this kind of issue.

  3. #3
    Join Date
    Oct 2007
    Posts
    15
    ??? I'm sorry, but can you be more descriptive?

    Thx

  4. #4
    Join Date
    Nov 2002
    Location
    New Jersey, USA
    Posts
    3,922
    Do you need to have the person active in all five states?. If only one is active and other four are for historical purpose, then you can use an indicator column in FACT table to indicate that, refer to "Slowly Changing Dimension" concept.

    If all five are active then you will need to create an associative table between fact table and dimension. It would turn your star schema into snowflake.

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