db-hw2 - Chapter Two Entity-Relationship Data Modeling:...

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Chapter Two Entity-Relationship Data Modeling: Tools and Techniques ANSWERS TO GROUP II QUESTIONS Use the STUDENT ACTIVITY IDEF1X diagram in Figure 2-32 to answer the following questions: 2.57 Consider the relationship between STUDENT and EQUIPMENT: A. What type is this relationship? Non-Identifying Connection Relationship B. What are the maximum cardinalities? The maximum cardinalities are 1:N. A STUDENT can have many EQUIPMENTs but an EQUIMENT can belong to only one STUDENT. C. What are the minimum cardinalities? The minimum cardinalities are zero on both sides. An EQUIPMENT does not require a STUDENT as indicated by the diamond. A STUDENT is not required to have an EQUIPMENT indicated by using the default. D. Describe any cardinality changes that you think should be made. Justify your changes. No changes. Since Students are no required to take course they would not be required to be assigned equipment. It is also possible that a course does not have students so the equipment may not be assigned to a student. E. Give an appropriate name for this relationship. Assigned/Assigned To 2.58 Consider the relationship between EQUIPMENT and COURSE: A. What type is this relationship? Non-Identifying Connection Relationship B. What are the maximum cardinalities? The maximum cardinalities are 1:N. A COURSE can have many EQUIPMENTs but an EQUIMENT can belong to only one COURSE. C. What are the minimum cardinalities? The minimum cardinalities are zero AND 1. An EQUIPMENT must be assigned to a COURSE (default cardinality). A COURSE is not required to have EQUIPMENT indicated by using the default. D. Describe any cardinality changes that you think should be made. Justify your changes. No changes. E. Give an appropriate name for this relationship. Uses/Used by 2-1
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Chapter Two Entity-Relationship Data Modeling: Tools and Techniques 2.59 In Figure 2-32, COURSE describes a course such as Beginning Kayaking or Intermediate Scuba; CLASS describes a particular offering of a course, such as the class Beginning Kayaking offered on January 7, 2003. For the relationship between COURSE and CLASS: A. What type is this relationship? Is this the correct type for this relationship? Identifying Connection Relationships since the key of the class would include the key of the course (course name). YES, the correct type of relationship is shown. B. What are the maximum cardinalities? The maximum cardinalities are 1:N. A COURSE can have many CLASSes but a CLASS can belong to only one COURSE. C. What are the minimum cardinalities? The minimum cardinalities are zero AND 1. A CLASS must be assigned to a COURSE (default cardinality). A COURSE is not required to have CLASSes indicated by using the default. D.
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db-hw2 - Chapter Two Entity-Relationship Data Modeling:...

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