Results 1 to 7 of 7
  1. #1
    Join Date
    Sep 2004
    Location
    Tampa, FL
    Posts
    520

    Unanswered: Is it bad Design ?

    In my current project I have the main Client table. This table has some clientinfo including the client number. (Actually it is BOPNum ) This field is my PK. I have 4 other tables that use this field as a FK. Is that a bad thing to have several tables use the same FK ?

    Mostly curious.
    Darasen

  2. #2
    Join Date
    Nov 2002
    Posts
    154

    Smile I don't know how it can be avoided

    In a third normal world, I'm not sure how you could design a database that didn't have multiple child tables based on a parent table. I think that, in the past, with slower servers it was a worry to have a fully normalized database. But, now servers are so damn fast for so little that I'm not sure that it is much of a concern anymore

  3. #3
    Join Date
    Sep 2003
    Location
    MI
    Posts
    3,713
    Quote Originally Posted by Darasen
    In my current project I have the main Client table. This table has some clientinfo including the client number. (Actually it is BOPNum ) This field is my PK. I have 4 other tables that use this field as a FK. Is that a bad thing to have several tables use the same FK ?

    Mostly curious.
    Nope. Good design ... Generally speking. What are these other 4 tables?
    Back to Access ... ADO is not the way to go for speed ...

  4. #4
    Join Date
    Sep 2004
    Location
    Tampa, FL
    Posts
    520
    Employment information, Transportation information, Case Notes, Subsistance information. Make that 5 Treatment information.
    Darasen

  5. #5
    Join Date
    Sep 2003
    Location
    MI
    Posts
    3,713
    Good design then ... Case in point: I have 1 table that has a PK and is related to 13 other tables with it's PK as a FK ...
    Back to Access ... ADO is not the way to go for speed ...

  6. #6
    Join Date
    Nov 2004
    Location
    out on a limb
    Posts
    13,692
    Provided Answers: 59
    There is no practical limit or rule which should dictate how many times a foreign key is used in a data model, it depends entirely on the real world problem you re modelling.

    Equally there is no practical limit or rule which should dictate how many column in a table should reference other tables PK. (Well except that the maximum is going to be No of columns -1 - ie you shouldn't have a PK in one table which is also a PK in another table, unless there are performance or data storage considerations overiding the rule). (ie you could have one table which has 5 or more columns which are FK's to other tables.

  7. #7
    Join Date
    Sep 2004
    Location
    Tampa, FL
    Posts
    520
    Coolness. I just wanted to double check. Looking at my relationships window compared to those you see in samples and the like it looks to be a bit messy. Hence, the question.
    Darasen

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •