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Multiplicity = Many !!!

 
raphael Bereh
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Can anyone tell me what is multiplicity Many ?
Is it (0,n) or (1,n) ?
In relation to the exam questions, how should you consider the following :
Custormer (1) <----> OrderBean (n)
What does the (n0 stand for : (0,n) or (1,n) ?
Thanks
 
Nathaniel Stoddard
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You can't have a relationship from 0 to n. It can be 1->1, 1->n, m->n (plus bidirectional).
[ April 26, 2004: Message edited by: Nathaniel Stoddard ]
 
raphael Bereh
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Sorry Nathaniel ,
Is that in EJB or UML ?
For instance a Java Programmer has 0 or n Sun Certifications !? Are you saying that if I put that in EJBs ProgrammerBean and CertificationBean, my multiplicity is wrong ?
 
Sujatha Kumar
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Hi Raphael,
Nathenial is talking about EJB.
Entity Relationship cannot be 0 to 1 or 0 to many.
It is a referential integerity (Primary key , Foreign key relationship)
Where as in UML, It is common among Objects to have 0 to 1 etc.
 
raphael Bereh
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Humm,
Well, you know how when dealing with multiplicity, you can on each side of the relation(ship) specify the Mininum and Maximun for the multiplucity !?
e.g : Programmer (0,n) <----> (0,n)Certification,so are you saying that in EJB, we only use the maximun for multiplicity ?, So the abose example would be : ProgrammerBean(n)<---->(n)CertificationBean - Many-to-Many - ?
 
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