Chapter 6 Normalization

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A headache This table has a key consisting of two attributes: ClientId, OfficeId → AccountNumber. AcctNumber ClientId OfficeId A057 1111 BS32 A908 1234 MN08 B123 1111 SB01 B123 2222 SB01 B321 3333 SB01 Assume we have to change the office affiliation of an account, e.g., B123, since we have a joint key, we can expect that multiple rows with the same OfficeId, SB01 in this case, but different ClientId, 1111 and 2222. Question: What happens if an account is jointly owned by 155 people 22
What is happening As a result, we have to locate all the rows showing different owners of this account, and change the associated office ID. In this case, we have two FDs, where a dependency of one FD AccountNumber → OfficeId, whose determinant, AccountNumber, is also a dependent of in another FD associated with the same table: ClientId, OfficeId → AccountNumber, Question: What would happen Answer: Redundancy. 23
Page 1 and 2: Chapter 6 Normalization Conceptual
Page 3 and 4: Remember this one Consider the foll
Page 5 and 6: Another abnormally Assume that we w
Page 7 and 8: Decomposition The solution to the a
Page 9 and 10: What have we learned 1. Decompositi
Page 11 and 12: Technically, ... ..., a functional
Page 13 and 14: FD examples Given the following val
Page 15 and 16: What do we really want We notice th
Page 17 and 18: Key is a special FD Note that the k
Page 19 and 20: Identify the FDs... Consider the ta
Page 21: The bad guy Consider the following
Page 25 and 26: What does that mean Every RDB is in
Page 27 and 28: The BCNF A relation schema S = (R,
Page 29 and 30: BCNF states that if this is the cas
Page 31 and 32: 4. A relation instance that is in a
Page 33 and 34: 5. BCNF relations with more than on
Page 35 and 36: 3NF could be redundant We saw earli
Page 37 and 38: A plan Since there is no redundancy
Page 39 and 40: An example Consider the following s
Page 41 and 42: An example The decomposition of Has
Page 43 and 44: A bit too late ..., which we will o
Page 45 and 46: BCNF Decomposition Let S 0 = (R, F)
Page 47 and 48: Via 3NF If we settle for 3NF, it is

Chapter 6 Normalization

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