sample exam-114-ANSWERS - 1...

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

View Full Document Right Arrow Icon
1. Explain multivalued attributes, and provide an example. How are multivalued  attributes indicated in the Chen model? How are they indicated in the Crow’s  Foot model? 2. What is a weak relationship? Provide an example. 3. What steps are involved in the conversion to third normal form? 4. Explain the BCNF. How is it related to other normal forms? 5. In what two cases are composite primary keys particularly useful? 6. Explain what a relationship is and list the different types of relationships 7. What is meant by a derived attribute? Illustrate by giving at leas t one example 8. What is meant by a A single-valued attribute? Illustrate by giving an example 9. Explain the meaning of a transaction in DBMS 10. What is the purpose of Concurrency Controls? 11. List the functions or responsibilities of the DBA
Image of page 1

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

View Full Document Right Arrow Icon
1.  Multivalued attributes are attributes that can have many values. For instance, a person may  have several college degrees, and a household may have several different phones, each with its  own number. Similarly, a car’s color may be subdivided into many colors (that is, colors for the  roof, body, and trim). In the Chen ERM, the multivalued attributes are shown by a double line  connecting the attribute to the entity. The Crow’s Foot notation does not identify multivalued  attributes.   (  ( REF: 108 TOP: Critical Thinking) 2  A weak relationship, also known as a non-identifying relationship, exists if the PK of the  related entity does not contain a PK component of the parent entity. By default, relationships are  established by having the PK of the parent entity appear as an FK on the related entity. For  example, suppose that the COURSE and CLASS entities are defined as:  COURSE(CRS_CODE, DEPT_CODE, CRS_DESCRIPTION, CRS_CREDIT) CLASS(CLASS_CODE, CRS_CODE, CLASS_SECTION, CLASS_TIME, ROOM_CODE,  PROF_NUM) In this case, a weak relationship exists between COURSE and CLASS because the  CLASS_CODE is the CLASS entity’s PK, while the CRS_CODE in CLASS is only an FK. In  this example, the CLASS PK did not inherit the PK component from the COURSE entity.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ 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