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Week 5 textbook assignment

Week 5 textbook assignment - several degrees and so then...

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Chapter 4 review questions 1, 3, 5, & 6 1. A weak entity is one that is: a. existence-dependent, meaning it can’t exist without the entity with which it has a relationship. b. has a primary key that is partially or totally derived from the parent entity in the relationship. A company insurance policy insures an employee and his dependents. In reference to an insurance policy the employee may or may not have a dependent , however a dependent must be associated with the employee . Furthermore, the dependent cannot exist without the employee . Dependent is the weak entity in the relationship, employee has dependent . 3. The business rule is “an employee can have many degrees” will affect the attributes, entities and relationships. The complexity of this situation will cause the creation of a unique table entity by the name of “emp_degree” and relate it to the “employee” entity. This creates a new attribute. The employee can easily have
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Unformatted text preview: several degrees and so then you would relate the two entities. 5. The customer owns the car; The car gets maintenance; Every car that gets maintenance has to have a maint_line; maint_line can have zero parts or many parts. Cardinalities: CUSTOMER (1:1) ______ owns_______ CAR (0:N) CAR (1:1) ____________ gets____________ MAINTENANCE (1:N) MAINTENANCE (1:1) ___ includes__ MAINT_LINE (1:N) MAINT_LINE (1:N) __ is written in___ PART (1:1) 6. A recursive relationship is when a relationship exists within the same entity. For example, an employee (who is also a manager) within the EMPLOYEE entity manages one or more other employees within that same entity. Therefore, EMPLOYEE has a relationship with itself. Problem 10 Having some trouble with this one....
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