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+7 votes
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Relations produced from an E-R model will always be in

a. 1NF
b. 2NF
c. 3NF
d. 4NF
asked in Databases by Loyal (6.2k points)
retagged by | 4.9k views
0
Can anyone explain this question in more detail?

3 Answers

+12 votes

1 NF.

Simple atomic values non multivalued attributes.

Generally ERD is design level task and Relational model is implementation. Whenever relational model is implemented from erd we get rid of  multivalued attribute. The procedure is outlined here: http://web.cse.ohio-state.edu/~gurari/course/cse670/cse670Ch9.xht. Multi-valued attributes are removed as M:N binary relation by repeating the tuples and hence relation becomes 1NF. We cannot guarantee any higher normalization. 

Student
SID Sname
1 Ram
2 Shyam
3 hari
SID Phone no
1 97772373733
1 97737377373
2 97873737337
2 97686373737

sid and phoneno both form the key in the new relation.

answered by Active (3.6k points)
0
link is not working
0
in the given example above both  relations are in BCNF right?

there is no partial dependency between non prime attribute and key

there is no transitive dependecy between non prime attribute and key through a non prime attribute

for every non trivial fd X --> A, X is a super key of the relation
+1 vote
there is no answer to this question

condition for a relation from e-r model is that it should not have a complex attribute(like address)

but relation from er model could have complex attribute

my guess would be
a.1NF
answered by Active (3.3k points)
0

What if multi valued attributes are present? Won't be 1 NF then!

0 votes

Relations produced from an E-R model will always be in 3NF

Answer is C

answered by Active (3.8k points)
0

naga praveen can you please explain ?

Answer:

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