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Unformatted text preview: 2007/2008 Tutorial 1 Answer Q1 : I) Entities: Departments, Employees, Supervisor, Projects II) Assigned (Employee-Department), Has (Department-Supervisor), Works-On (Employee-Project), III) The only attributes indicated are the names of the departments, projects, supervisors and employees, as well as the supervisor and employee SSN and a unique project number. IV) The primary keys are Department_No (Dept_ Name is also acceptable), Supervisor No (same as the supervisor’s emp_no), Employee No, Project Number. Q2 : I) The entities in this system are DRIVER (a role), VEHICLE (a tangible item), LOAD (an event), EXPENSE (an event), STOP (a location) and ITEM (a tangible item). Most of these entities are evident from the wording in the problem. What may not be clear is the need for both LOAD and ITEM. A LOAD is the contents of a truck on a single trip. A LOAD contains many ITEMS which are dropped off at the various STOPs. Note that DEPOT is not an entity since it has only one instance. ii) Find Relationships DEPARTMENT SUPERVISOR EMPLOYEE PROJECT Assigned Works_on Has 2007/2008 Drive r Driver Vehicle Load Expense Stop Item Vehicle Driven b y ( M : M ) Load Carries (1: 1) Expense Incurs ( M : M ) Stop Left at Item Consists o f ( M : M ) iii) The following data attributes were identified: DRIVER-NO, NAME, HOME-...
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- Winter '09
- Computer Programming, Entity-relationship model, State PostCode Phone, PostCode Phone Number