ER To Relation

Question

 

Comments

10 ??

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i think it is 11 how u got 10

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1. F (c, d)

2. E (a, c , b)

3. G(a, e)

4. H(g, h)

5. S ( e ,f  ,g) (Many to Many relation )

Total =  12

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kumar.dilip in your comment I guess 4 is H(g,h)

and in 5, why you considered only 'g'(which is not a key). According to me, S(e,f,g,h) should be there.

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@Utkarsh Joshi

My mistake, I edited that.

But g is key int the H.

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I have a doubt here:

E(a,b,c)

F(c,d)

Now the property of specialization is that the attributes of higher level entity is inherited by lower level entity set So the attributes a,b,c should be inherited to G giving G(a,b,c,e)

S(e,f,g)

H(g,h)

So total attributes should be:- 14

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Ace Solution::

Why didnt they inherited b in G ? or does inheriting all attributes of higher level entity means to inherit only the primary key because using that eventually i can access all records of it.

And in S(a,e,g,f) i guess both primary keys are inherited of higher level as well as that level too.

Please point out where i'm wrong if am wrong.

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@arjun sir please help.

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meaning of this symbol and name of this symbol ??

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Its Specialization