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  3. a in this figure which attribute is a key for...

Question: a in this figure which attribute is a key for...

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Fname Minit Lname Bdate Name 〉(Address)( Salary Ssn Sex Locations WORKS_FOR Name Number EMPLOYEE Start dateNumber_of_employees DEPARTMENT MANAGES CONTROLS Hours WORKS_ON PROJECT Supervisor Supervisee1 1SUPERVISION N Name Location Number DEPENDENTS OF DEPENDENT Name Sex Birth date Relationship Figure 3.2 An ER schema diagram for the COMPANY database. The diagrammatic notation is introduced gradually throughout this chapter and is summarized in Figure 3.14.

a) In this Figure, which attribute is a “key” for the Employee entity?

b) What kind of an attribute (of Employee) is Name? (hint: starts with a C)

c)   In the Supervision relationship, is it permitted for a supervisee (i.e., a typical employee) to have more than one Supervisor? In the diagram, why do you say that?

d) Why are there double lines in the entity box for Dependent? What kind of an entity is Dependent?

e) Why are the Name and the Number attributes of Department underlined?

f) What do the double lines around the oval for Locations mean?

g) In the Works_For relationship, can an Employee work for more than one Department?   Why do you say that?

h) Why is the oval for Number_of_Employees a dashed line? What type of attribute is this? What does that mean?

i) Why might it make organizational and computer performance sense for the Number_of_Employees attribute to be this special kind of attribute in part (h) rather a regular attribute with a pre-specified value?

j) Is the “participation” of Employee in the Works_On relationship Total or Partial? How do you know this?

k) Is it permitted in this model for an Employee NOT to have a Works_On relationship with at least one project? How do you know that?

L) Can an Employee work on more than one project? How do you know that?

m) In this model, can an Employee have a Works_For relationship with more than one Department? How do you know that?

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