Determine candidate and primary key, Database Management System

  • A video rental company has several branches.
  • The data held on each branch is the branch address made up of street, city, state, and zip code, and the telephone number.
  • Each branch is given a branch number, which is unique. Each branch is allocated staff, which includes a Manager. The Manager is responsible for the day-to-day running of a given branch.
  • The data held on a member of staff is his or her name, position, and salary. Each member of staff is given a staff number, which is unique.
  • Each branch has a stock of videos. The data held on a video is the catalog number, video number, title, category, daily rental, cost, status, and the names of the main actors, and the director. The catalog number uniquely identifies each video. However, in most cases, there are several copies of each video at a branch, and the individual copies are identified using the video number.
  • A video is given a category such as Action, Adult, Children, Drama, Horror, or Sci-Fi. The status indicates whether a specific copy of a video is available for rent.
  • Before hiring a video, a customer must first register as a member. The data held on a member is the first and last name, address, and the date that the member registered at a branch.
  • Each member is given a member number, which is unique. Once registered, a member is free to rent videos, up to maximum of ten at any one time.
  • The data held on each video rented is the rental number, the name and number of the member, the video number, title, and daily rental, and the dates the video is rented out and date returned. The rental number is unique.

(a)   Identify the main entity types of the company.

(b) Identify the main relationship types between the entity types and determine the multiplicity constraints for each relationship

(c)   Identify attributes and associate them with entity or relationship types.

(d)  Determine candidate and primary key attributes for each (strong) entity type.

(e)  Using your answers (a) to (d) create a single ER diagram. State any assumptions necessary to support your design.

Posted Date: 2/21/2013 6:41:43 AM | Location : United States

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