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Draw an ER diagram of library management

    Question

  • I have to draw the ER diagram of library management base on these following requirements:

    "The library has books, CDs, tapes, and so forth, which are lent to library patrons. The latter have accounts, addresses, and so forth. If a patron is a minor, she/he must have one sponsoring patron who will be responsible for paying any penalties incurred by the minor. Information must be recorded to identify items that are overdue. Each type of items (tapes, CD, books, etc.) for loan has its own loan period, and penalty rate for overdue loans. Include in your E-R diagram information about keys and constraints if any.

    You should come up with 2 different ER diagram, i.e., with and without the IsA construct. Which one would you prefer? Justify your preference, in comparing the database schemas into which ER diagrams may be converted."

    There are what I've done, but I'm not sure they are correct or not, and which one between diagram 2 and 3 are correct?

    ER diagram 1

    ER diagram 2

    ER diagram 3

    can anyone check over for me and give me some ideas about the constraints between entities?

    Thanks in advance

    Thursday, May 30, 2013 11:27 PM

Answers

  • I have to draw the ER diagram of library management base on these following requirements:

    "The library has books, CDs, tapes, and so forth, which are lent to library patrons. The latter have accounts, addresses, and so forth. If a patron is a minor, she/he must have one sponsoring patron who will be responsible for paying any penalties incurred by the minor. Information must be recorded to identify items that are overdue. Each type of items (tapes, CD, books, etc.) for loan has its own loan period, and penalty rate for overdue loans. Include in your E-R diagram information about keys and constraints if any.

    You should come up with 2 different ER diagram, i.e., with and without the IsA construct. Which one would you prefer? Justify your preference, in comparing the database schemas into which ER diagrams may be converted."

    This sounds very much like homework/assignment...

    If you have done your work studiously, I am sure you can ask your tutor for his/her opinions before submission.

    You can also check your work against the data models offerred in the Library of Data Models from Database Answers. There are 15 models in the "Library" section so there are plenty for you to work with.

     


    Van Dinh

    Saturday, June 01, 2013 12:22 AM

All replies

  • I have to draw the ER diagram of library management base on these following requirements:

    "The library has books, CDs, tapes, and so forth, which are lent to library patrons. The latter have accounts, addresses, and so forth. If a patron is a minor, she/he must have one sponsoring patron who will be responsible for paying any penalties incurred by the minor. Information must be recorded to identify items that are overdue. Each type of items (tapes, CD, books, etc.) for loan has its own loan period, and penalty rate for overdue loans. Include in your E-R diagram information about keys and constraints if any.

    You should come up with 2 different ER diagram, i.e., with and without the IsA construct. Which one would you prefer? Justify your preference, in comparing the database schemas into which ER diagrams may be converted."

    This sounds very much like homework/assignment...

    If you have done your work studiously, I am sure you can ask your tutor for his/her opinions before submission.

    You can also check your work against the data models offerred in the Library of Data Models from Database Answers. There are 15 models in the "Library" section so there are plenty for you to work with.

     


    Van Dinh

    Saturday, June 01, 2013 12:22 AM
  • I've asked my instructor, but he won't check for me until I submit my assignment officially. However, If I do that, I can't change anything and my assignment will be marked. I just need someone to check for me to see if my ER diagrams are correct or not and give me some advices.
    Saturday, June 01, 2013 8:18 AM
  • Your instructor is stricter than my experience.  When I was in uni. and provided that the instructors saw the proof of the work I put in, they virtually gave me the solutions of the assignments.

    He/she wants to see your understanding of the subject, not mine in this case so I can't suggest changes if required (I haven't seen your diagrams).  I suspect that a lot of respondents will feel the same.

    Suggest you check your ER/data model against the data models from Database Answers whose link I posted earlier and see if your data model is similar to the Database Answers data models as an additional check on your own.

      


    Van Dinh


    • Edited by Van DinhMVP Saturday, June 01, 2013 12:28 PM Typos
    Saturday, June 01, 2013 10:34 AM
  • Thank you!!
    Saturday, June 01, 2013 6:06 PM
  • Can you add participation constrains and cardinality ratio in your diagrams?

    Regards, RSingh

    Monday, June 03, 2013 5:03 AM
  • A

    The "ER" model is not an ER model. They are trying to teach you decomposition, analysis and following the 3 standard rules of 3rd normal form. You have an attempt at a data flow diagram something Data Analyst will give you and let you do your ER design work all traceable to a requirements document.

    Look for nouns, put that in a single column in a spreadsheet. 2nd column are the descriptions of your first column. Analize what you have and find a common entity that exist on its own with your second column that describes that entity as unique. Name, person, product are entities. Type, color price are attributes that describe the entity. Once you have a list of potential entities and attributes that describe your entities you are ready for first normal form and more analysis.


    Hope this is Helpfull. J Alverson Microsoft BI Solutions Please use Marked as Answer if my post solved your problem and use Vote As Helpful if a post was useful.


    • Edited by J Alverson Monday, June 03, 2013 11:58 PM add value
    Monday, June 03, 2013 11:44 PM
  • you can implement cardinality relationships (like M : N / N : 1 etc)

    Mark as answer if this solves your problem. ... Best Regards D. Chatterjee MCA, RERF

    Tuesday, June 04, 2013 10:28 AM