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Thread: ERD Help

  1. #1
    Join Date
    Nov 2014
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    ERD Help

    I've been given an assignment about a hospital. In a particular paragraph it states that:


    "A pack can be used in a blood transfusion. A transfusion consists of one or more packs being given to a recipient on a particular date. Unfortunately, when the donation is tested the donor might be found to be unwell. In this case the donor is advised to see their general practitioner (GP) and the donation is wasted (cannot be used)."

    I Believe that from this paragraph an entity for Transfusions can be merged, taken into account that previously I outlined Pack as an entity as well. Now when it states that "A transfusion consists of one or more packs being given to a recipient on a particular date." does it mean that a particular data has to be an attribute in an entity?

  2. #2
    Join Date
    Nov 2014
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    I believe you think of such a situation:

    Click image for larger version. 

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    https://my.vertabelo.com/public-mode...=4709&zoom=1.0

    This should solve all the doubts.

  3. #3
    Join Date
    Nov 2014
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    Quote Originally Posted by patrycja View Post
    I believe you think of such a situation:

    Click image for larger version. 

Name:	dbforums_1.png 
Views:	5 
Size:	10.9 KB 
ID:	15962

    https://my.vertabelo.com/public-mode...=4709&zoom=1.0

    This should solve all the doubts.
    Thanks a lot. What about the GP? Should I also include it as an entity?

  4. #4
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    If the case study requires interaction with the GP then how do you think that should be handled. This is, after all, your homework


    Often these things are down to semantics
    however I would expect a blood donation/pack to exist without a direct link, or association with a transfusion. As in the event the donor is deemed unwell the donation is disposed of. That would infer to me that you may need something else to define the use of a blood donation and then something else that handles the disposition of each specific donation
    Last edited by healdem; 11-13-14 at 02:28.
    I'd rather be riding on the Tiger 800 or the Norton

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