Ace Test Series: Databases - Er Diagram

Question

Comments

ssn?

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Answer is b Cid.

Professor is in total participation and Course is in partial participation. There may be possibility that one or more entity in Course takes part in relation ship. But we need to store the course.

SSn	Name	Cid	Cname
1	A	10	CN
null	null	11	DS

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yes, answer is cid.

ssn may be null, so {ssn,cid} can not be the PK.

Answer 1

Both arrows are pointed to the relation which indicates a key constraint, so both of them are total participating in the relation and participates exactly in one relation ship,

so it is one - to -one so both having total participation due to key constraint so both A and B are correct

Comments

@sushant this is given in raghuram krishnan...see chapter 3 there

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@sudsho. Thanks. Will surely check.

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but how can it be one to one because 1 faculty can teach 1 course but 1 course has more than 1 faculty or n faculies.

that is the relationship is becoming n:1 ( faculty -- course ) .

Answer 2

Answer will be C