Boyce-Codd Normal Form (BCNF) Definition R in 1NF and Every determinant (the left side of a FD) is a...

Boyce-Codd Normal Form (BCNF)

Definition

R in 1NF and

Every determinant (the left side of a FD) is a candidate key.

1

Not in BCNFSchedule (staffNo, dentistName, patNo, patName, surgeryNo, date, time)

PK: surgeryNo, Date, Time

FDs:

surgeryNo, Date, Time ===> staffNo, patNo (All)

staffNo, Date, Time ===> surgeryNo, patNo (All)

patNo, Date, Time ===> staffNo, surgeryNo (All)

(The determinants are candidate keys)

staffNo ===> dentistName (transitive on PK)

patNo ===> patName (transitive on PK)

staffNo, Date ===> surgeryNo (surgeryNo is a PK attribute!)

(The determinants are NOT candidate keys)

2

Different PKSchedule (staffNo, dentistName, patNo, patName, surgeryNo, date, time)

PK: staffNo, date, time

AK: surgeryNo, date, time

patNo, date, time

FK: None

staffNo, Date, Time ===> patNo, surgeryNo (All)



staffNo ===> dentistName (partial on PK)

patNo ===> patName (transitive on PK)

staffNo, Date ===> surgeryNo (partial on PK!)3

Schedule (staffNo, dentistName, patNo, patName, surgeryNo, date, time)

PK: surgeryNo, Date, Time

FDs:




staffNo ===> dentistName (determinant is NOT candidate key)

patNo ===> patName (determinant is NOT candidate key)

staffNo, Date ===> surgeryNo (determinant is NOT candidate key)

New Tables in BCNF

Staff (staffNo, dentistName)

Patient (patNo, patName)

RoomAllocation (staffNo, Date, surgeryNo)

Schedule (staffNo, patNo, date, time)

PK & FK!4


PK: staffNo, date, time

AK: patNo, date, time

FK: staffNo references Staff

patNo references Patient

staffNo, Date references Room

FDs:

staffNo, Date, Time ===> patNo

patNo, Date, Time ===> staffNo

PK and AK can be switched.

5


PK: patNo

AK: None

FK: None

FDs:

patNo ===> patName


PK: staffNo

AK: None

FK: None

FDs:

staffNo ===> dentistName

RoomAllocation (staffNo, Date, surgeryNo) PK: staffNo, Date AK: None FK: staffNo references Staff staffNo, Date ===> surgeryNo

6


PK: staffNo

AK: None

FK: None

FDs:

staffNo ===> dentistName

staffNo dentistName

------------- --------------------

S1011 Tony Smith

S1024 Helen Pearson

S1032 Robin Plevin

dentistName will be removed from the original table,

But staffNo remains in the original table.

7


PK: patNo

AK: None

FK: None

FDs:

patNo ===> patName

patNo patName

------------ -------------------

P100 Gillian White

P105 Jill Bell

P108 Ian MacKay

P110 John Walker

patName will be removed from the original table,

But patNo remains in the original table.

Not in BCNFSchedule (staffNo, dentistName, patNo, patName, surgeryNo, date, time)

Schedule (staffNo, patNo, surgeryNo, date, time)

FDs:




staffNo, Date ===> surgeryNo

(The determinants are NOT candidate keys)

8

9

RoomAllocation (staffNo, Date, surgeryNo)

PK: staffNo, Date

AK: None


FDs:

staffNo, Date ===> surgeryNo

staffNo Date surgeryNo

---------- ------------ --------------

S1011 12-Sep-04 S15

S1024 12-Sep-04 S10

S1024 14-Sep-04 S10

S1032 14-Sep-04 S15

S1032 15-Sep-04 S13

surgeryNo will be removed from the original table,

But staffNo and Date remains in the original table.

10


PK: patNo, date, time

AK: staffNo, date, time


patNo references Patient

staffNo, Date references RoomAllocation

FDs:

staffNo, Date, Time ===> patNo

patNo, Date, Time ===> staffNo

staffNo patNo date time

---------- ---------- ------------- ----------

S1011 P100 12-Sep-04 10:00

S1011 P105 12-Sep-04 12:00

S1024 P108 12-Sep-04 10:00

S1024 P108 14-Sep-04 14:00

S1032 P105 14-Sep-04 16:30

S1032 P110 15-Sep-04 18:00

Boyce-Codd Normal Form (BCNF) Definition R in 1NF and Every determinant (the left side of a FD) is a...

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