Objective: this assignment is designed to let you have a hands-on experience wit

Question

Objective: this assignment is designed to let you have a hands-on experience with normalization. A normalized schema provides a good starting point for further development of a database application and easier maintenance it lat Nomalization is a process of modifying an existing database schema to bring its component tables into compliance with a series of normal forms. The goal of the normalization is to ensure that every non-key attribute in every table is directly dependent on the whole candidate key (nothing else but the key) 1. Consider a relation R with five attributes A, B, C, D, . You givn elowing dependences: C? E BC? D ED ? C swer Answer 2. Consider the relation F with six attributes ERID,A,Y with thoowing dependence: FD Y FY ? A, and FA ?R. a) List all keys for F and justify your answer Answer:

Explanation / Answer

1. candidate key is a minimal superkey.it identifies all tuples of relation uniquely.

R(A,B,C,D,E) is the relation and having given following Functional dependencies :

C->E

BC->D

ED->C

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Let us Check ABCE is Candidate Key or not for this relation

If we take attribute closure of

(ABC)+ -> (ABC) [Due to trival dependencies]

(ABC)+ -> (ABCE) [given C->E]

(ABC)+ -> (ABCDE) [given BC->D]

so by using ABC we can find all attributes of a rleation.

So if we add any attributes to ABC like D or E it will become Super key.

So we get ABCE is a superkey not a candidate key

ABC is a candidate key of relation.

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