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  1. #1
    Join Date
    Apr 2013
    Posts
    4

    Question Should I use super & subtypes in my ERD?

    A manager has many employees, and a manager can be assigned to one or many locations.

    An employee can choose items and this is stored in orders and many staff are assigned to many departments.

    There are employees, managers and administrators stored in the staff table and a manager manages employees. Does this ERD satisfy the requirements?

    Another consideration if this system was to grow really big over years of use would this be practical?

    Many Thanks

    Should I create a supertype of staff with sub types of admin, employees and managers?

    https://www.dropbox.com/s/vw54nup50wlgihm/erd.PNG

  2. #2
    Join Date
    Apr 2013
    Posts
    4

    Question ERD diagram for item retrieval system

    A manager has many employees, and a manager can be assigned to one or many locations.

    Working on a backend database for a client

    An employee can choose items and this is stored in orders and many staff are assigned to many departments.

    There are employees, managers and administrators stored in the staff table and a manager manages employees. Does this ERD satisfy the requirements?

    Another consideration if this system was to grow really big over years of use would this be practical?

    Many Thanks

    Should I create a supertype of staff with sub types of admin, employees and managers?

    https://www.dropbox.com/s/vw54nup50wlgihm/erd.PNG

  3. #3
    Join Date
    Feb 2004
    Location
    In front of the computer
    Posts
    15,579
    Depending on the size of the organization, managers can manage other managers. There's always someone at "the top of the food chain" with no manager. In some organizations there are autonomous employees (no manager, no subordinates). Which of these apply to your case, and how will you handle them?

    I'd guess that the customer actually orders the items, not an employee. How does the customer fit in your model?

    Having a staff or a person super-type makes many things easier, but not all systems handle the added complexity of sub-types well. Will the additional complexity of dealing with sub and super types be offset by the simplicity that they bring to other operations?

    -PatP
    In theory, theory and practice are identical. In practice, theory and practice are unrelated.

  4. #4
    Join Date
    Apr 2013
    Posts
    4
    Hello there are no customers involved in the system I am creating. It is a simple system that allows employees to retrieve awards.

  5. #5
    Join Date
    Apr 2013
    Posts
    4
    Admins can add managers and managers can add employees. so managers handle many employees in one location

    Thanks

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