locked
How to organize the ERD RRS feed

Answers

  • Smaller diagrams will be more readable. You can take tables describing some area (security, invoicing...) and put them into separate diagrams. You can follow Brian's post, but this would be not an easy task in SSMS - it is not a database modelling tool. There are specialized tools to do this work (Power Designer...) on the market.

    MP.

    Friday, May 21, 2010 2:35 PM
  • There are many different ways to do it. I will list three that i know of.

    Jumble - Just get the relationships defined, that's what people want.
      Easy to make, and hard to use.
      Most people won't complain as they'll just follow the lines as needed.

    Star - Major entities surrounded by related TABLEs. If a TABLE is used twice, use shadows (copy of a TABLE already in the design). Major entities are connected to each other by longer lines to help separate them.
      Programmers like this one, because they can focus in on the entity they are dealing with and get related entities.
      Need to make sure to get major entities right, or the stars are useless.
      Difficult to see where each lookup is used.

    Hierarchical - All TABLEs with no parent go on top, children on next level, their children on next level.
      Hardest to make and upkeep.
      Useful for designers the whole picture, and to segment hierarchies of data.
      Some places do bottom up instead.

    My preference is Hierarchical. The Jumble is useless to me, and the Star missed the entire picture. When i changed a Star to a Hierarchical, i got many thanx because segments were more easily seen. YMMV.

    Friday, May 21, 2010 2:13 PM
    Answerer
  • Hello,

    There is a button Arrange Tables on the toolbar in Management Studio. I would reccommend you to create more subject oriented database diagrams containing smaller number of tables...

    Miloslav Peterka.

    Friday, May 21, 2010 2:15 PM

All replies

  • There are many different ways to do it. I will list three that i know of.

    Jumble - Just get the relationships defined, that's what people want.
      Easy to make, and hard to use.
      Most people won't complain as they'll just follow the lines as needed.

    Star - Major entities surrounded by related TABLEs. If a TABLE is used twice, use shadows (copy of a TABLE already in the design). Major entities are connected to each other by longer lines to help separate them.
      Programmers like this one, because they can focus in on the entity they are dealing with and get related entities.
      Need to make sure to get major entities right, or the stars are useless.
      Difficult to see where each lookup is used.

    Hierarchical - All TABLEs with no parent go on top, children on next level, their children on next level.
      Hardest to make and upkeep.
      Useful for designers the whole picture, and to segment hierarchies of data.
      Some places do bottom up instead.

    My preference is Hierarchical. The Jumble is useless to me, and the Star missed the entire picture. When i changed a Star to a Hierarchical, i got many thanx because segments were more easily seen. YMMV.

    Friday, May 21, 2010 2:13 PM
    Answerer
  • Hello,

    There is a button Arrange Tables on the toolbar in Management Studio. I would reccommend you to create more subject oriented database diagrams containing smaller number of tables...

    Miloslav Peterka.

    Friday, May 21, 2010 2:15 PM
  • Hello,

    There is a button Arrange Tables on the toolbar in Management Studio. I would reccommend you to create more subject oriented database diagrams containing smaller number of tables...

    Miloslav Peterka.


    hello miloslav,

    what do you mean by more subject oriented diagram

    and i tried the arrange button it doesnt make the erd easy to read

    thanx for help

    Friday, May 21, 2010 2:26 PM
  • hello

    i will try them and find which one is best

    and could you tell me if there is a book or an articale discuse these ways

    thanx for helping

    Friday, May 21, 2010 2:31 PM
  • Smaller diagrams will be more readable. You can take tables describing some area (security, invoicing...) and put them into separate diagrams. You can follow Brian's post, but this would be not an easy task in SSMS - it is not a database modelling tool. There are specialized tools to do this work (Power Designer...) on the market.

    MP.

    Friday, May 21, 2010 2:35 PM
  • No books. I just have seen the first two, and used the third on my own.

    If you start doing what makes sense. You will find your preference. Just be consistent.

    Friday, May 21, 2010 2:37 PM
    Answerer
  • thanx for both of you

    that was helpfull

    mohammad fares

    Friday, May 21, 2010 6:34 PM