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  1. #1
    Join Date
    Dec 2006
    Posts
    8

    Question Need some help with ERD

    hi every1..

    i'm a new oracle learner and new in this forum too i hope u can help me be good at oracle, for a start i'd like to ask some questions:

    1- about time constraints, which of the following would be a logical constraint when modeling time for a country entity?
    A) People have births and deaths in their countries that must be tracked by the system
    B) If you are doing a system for France or Germany, you would need security clearance
    C) Countries may need an end date in your system, because they can change fundamentally over time, e.g. Thailand used to be Siam, Sri Lanka used to be called Ceylon
    D) You need a constant record of countries, because they are still countries, even if leadership changes over time, e.g. France


    2- What is the benefit to the users of a system that includes "time," e.g. Start Date and End Date for Employees?
    A) Increased usability of a system; allows users to work in advance
    B) System becomes 100% in flux; allows users to log on and log off at will
    C) Users are able to create complex programs in support of this component
    D) Journaling becomes nearly impossible, users enjoy this

    3- can this be a structural business rule: "Each shelter contains dogs, cats and occasionally another type of animal, like birds or snakes."

    with explaination plz
    thanks..

  2. #2
    Join Date
    Jun 2003
    Location
    West Palm Beach, FL
    Posts
    2,713

    Thumbs down


    Is this some kind of homework quiz?
    Did you do some research on your own before posting?
    ERD is surely related to modeling and modeling is related to database design, but where in this picture does Oracle fit in? Maybe you need to post this in a design related forum.
    The person who says it can't be done should not interrupt the person doing it. -- Chinese proverb

  3. #3
    Join Date
    Dec 2006
    Posts
    8

    Question some questions on ERD

    hi every1..

    i'm a new oracle learner and new in this forum too i hope u can help me be good at ERD, for a start i'd like to ask some questions:

    1- about time constraints, which of the following would be a logical constraint when modeling time for a country entity?
    A) People have births and deaths in their countries that must be tracked by the system
    B) If you are doing a system for France or Germany, you would need security clearance
    C) Countries may need an end date in your system, because they can change fundamentally over time, e.g. Thailand used to be Siam, Sri Lanka used to be called Ceylon
    D) You need a constant record of countries, because they are still countries, even if leadership changes over time, e.g. France


    2- What is the benefit to the users of a system that includes "time," e.g. Start Date and End Date for Employees?
    A) Increased usability of a system; allows users to work in advance
    B) System becomes 100% in flux; allows users to log on and log off at will
    C) Users are able to create complex programs in support of this component
    D) Journaling becomes nearly impossible, users enjoy this

    3- can this be a structural business rule: "Each shelter contains dogs, cats and occasionally another type of animal, like birds or snakes."

    with explaination plz
    thanks..

  4. #4
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    weirdest homework questions i've seen in a long time

    what are your answers for these questions? and please give reasons
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  5. #5
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    threads merged
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  6. #6
    Join Date
    Dec 2006
    Posts
    8
    well i don't understand the concept of adding time in database design, thats why i was hoping that someone could explain these questions simply, as for business rule i think its true, just wanted to make sure..
    and yes i searched a lot before posting, i never ask a question unless i searched for the answer and found nothing, and srry for posting it in the wrong place, i didn't see the design section..

  7. #7
    Join Date
    Apr 2002
    Location
    Toronto, Canada
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    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  8. #8
    Join Date
    Dec 2006
    Posts
    8
    hi
    thanks for your help, i read the sites, i understood the overall idea, but still need some details about how to do this on ERD, and i still can't figure out an answer for the above questions..
    thnks again..

  9. #9
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    well, you are going to have to do some more digging, becuase i'm not going to hand you the answers

    were you given no resources for this course? no book?
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  10. #10
    Join Date
    Dec 2006
    Posts
    8
    no i'm self learning.. and i don't want the answers directly, i just want a simple explaination that could get me to answer these questions..

  11. #11
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    congratulations

    if you are self learning, then how about giving it a try?

    how would you answer those questions? please give reasons for your choice

    come on, it's not that hard -- try
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  12. #12
    Join Date
    Dec 2006
    Posts
    8
    well for the first one i'd say it's A, it's not B since i don't need any confidintial info. to get security clearance, and not C or D because they just don't make since (i don't get it clearly maybe)

    A for the second one too, not B because using time don't allow users to log on and log off at will, defenatly not D, as for C (i don't get it)

    for the last one i don't see anything prevents it from being a business rule (except if structural business rules are diffrent from business rules)

    that's all -srry 4 bad english-

    so.....
    Last edited by Sub_Zero_6; 12-01-06 at 19:11.

  13. #13
    Join Date
    Apr 2002
    Location
    Toronto, Canada
    Posts
    20,002
    for question 1, which options have anything to do with a time constraint?

    for question 2, which options have anything to do with a start and end dates?

    for question 3, what is your definition of "a structural business rule"?
    rudy.ca | @rudydotca
    Buy my SitePoint book: Simply SQL

  14. #14
    Join Date
    Jun 2005
    Posts
    13
    Quote Originally Posted by Sub_Zero_6
    hi every1..

    i'm a new oracle learner and new in this forum too i hope u can help me be good at oracle, for a start i'd like to ask some questions:

    1- about time constraints, which of the following would be a logical constraint when modeling time for a country entity?
    A) People have births and deaths in their countries that must be tracked by the system
    B) If you are doing a system for France or Germany, you would need security clearance
    C) Countries may need an end date in your system, because they can change fundamentally over time, e.g. Thailand used to be Siam, Sri Lanka used to be called Ceylon
    D) You need a constant record of countries, because they are still countries, even if leadership changes over time, e.g. France


    2- What is the benefit to the users of a system that includes "time," e.g. Start Date and End Date for Employees?
    A) Increased usability of a system; allows users to work in advance
    B) System becomes 100% in flux; allows users to log on and log off at will
    C) Users are able to create complex programs in support of this component
    D) Journaling becomes nearly impossible, users enjoy this

    3- can this be a structural business rule: "Each shelter contains dogs, cats and occasionally another type of animal, like birds or snakes."

    with explaination plz
    thanks..
    Hi Sub_Zero_6, I dont have a smilie for rolling on the floor laughing my butt off, but if I did it would be inserted here now!

    Where did u get these questions and answers from? If the answer is "I thought them up" then you need to do a whole lot more research, but if the answer is "someone gave them to me" then they are being very obtuse!

    Either way, without knowing the full application domain and business rules of what you are trying to model then what you have presented there is just incoherent nonsense!

    If these are supposed to be part of some tutoring or assignment you have then they are very vague and I think guessing at the meaning and the answers for you is pointless. Any assignment should come with tutoring first so you at least understand the assignment!
    Last edited by amvam; 12-01-06 at 20:31.

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