1. Consider the relation schemas: faculty student (SSN, last-name, first-name, s
ID: 3723972 • Letter: 1
Question
1. Consider the relation schemas: faculty student (SSN, last-name, first-name, street, city, state) (SSN, last-name, first-name, street, city, state) and the following instance: last-name first-name street SSN city state 388-67-9009 Bai 980-67-8765 Jackson Perkins Baton Rouge LA Lu Baton Rouge LA Baton Rouge LA Courtney Washington Baton Rouge LA Ma Tina lowa State- 435-67-2342 Charles Is this instance a legal instance of relation faculty? Why? a. b. Is this instance a legal instance of relation student? Why?
Explanation / Answer
A).YES,this instance is a legal instance of relation faculty.
In faculty relation,last-name is primary key,therefore it does not matter at what time or instance we consider instance of relation faculty ,the last-name must be unique.
Under attribute last-name,all the values or tuples are unique.so,this is legal instance of relation faculty.
B).NO,this instance is not a legal instance of relation Student.
Primary key of relation student is SSN.therefore,under attribute SSN,all the tuples needs to be unique.but here are two tuples or values under attribute SSN which are same.i.e tuple 2 & 3 has same value 980-67-8765.due to this reason,it is not a valid instance of relation student.
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