doc10 - 1 Relationships illustrate association between two...

Info icon This preview shows pages 1–3. Sign up to view the full content.

1) Relationships illustrate association between two or more entities. In physical data model, these relations will be represented by lines. The maximum/minimum number of times an instance in one entity is associated with an instance in related entity refers to the cardinality. Cardinality can be classified as – i. One-to-One : It represents relationship between entities in which one occurrence of data in one entity might have one occurrence of data in related entity. 1 1 ii. One-to-many : It represents relationship between entities in which one occurrence of data in one entity might have one or more occurrence of data in related entity. 1 n iii. Many-to-many: This relationship exists if multiple occurrences of related data are allowed to exist between two entities in either direction. n n a. A pet and store have one-to-many relationship as a pet can be sold in ‘n’ number of stores.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.
  • Fall '16
  • Data Structures, Entity-relationship model, Related Entity, one-to-many relationship

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern