and a list of products price and quantity for the products that the customer

And a list of products price and quantity for the

This preview shows page 21 - 28 out of 28 pages.

and a list of products, price, and quantity for the products that the customer wants delivered. The attributes {PRODUCT, PRICE, QUANTITY} constitute a repeating group.
Image of page 21
Information Access Mgt 09/12/97 3 Example: Order ORDER PRODUCT PRICE QUANTITY 5103 IRON 17.95 11 SKILLET 19.95 6 5110 TOASTER 57.95 4 IRON 17.95 3 Each instance of an order has several order lines. Order lines {Description, Price, Quantity} are examples of repeating groups .
Image of page 22
Information Access Mgt 09/12/97 3 RELATIONSHIP. Does not describe processing or change any data. Relationship names should be passive (ordered by). CARDINALITY Refers to the number of records that a relationship connects to a given child record in a relationship. PARTICIPATION (Optionality) Refers to whether a record must exist in one table before a related one is inserted into another.
Image of page 23
Information Access Mgt 09/12/97 3 Diagrams: 1:m Relationships Section Instructor CourseSection InstructorID InstructorID
Image of page 24
Information Access Mgt 09/12/97 4 Diagrams: m:n Relationships Section Student CourseSection StudentID Student-Section CourseSection StudentID
Image of page 25
Information Access Mgt 09/12/97 4 Optionality (Referential Integrity) Records in a table that have a relationship with another table may be restricted by optionality requirements. Relationship Optional Relationship Mandatory (referential integrity enforced)
Image of page 26
Information Access Mgt 09/12/97 4 Optionality 0 1 Optional (0 allowed) Mandatory (1 or more required)
Image of page 27
Information Access Mgt 09/12/97 4 Data
Image of page 28

You've reached the end of your free preview.

Want to read all 28 pages?

  • Fall '16
  • jeoramedelubio
  • Entity-relationship model

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

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask You can ask (will expire )
Answers in as fast as 15 minutes
A+ icon
Ask Expert Tutors