Boyce-Code Normal Form (BCNF)

BCNF is an extension of Third Normal Form (3NF) and is slightly stronger than 3NF.

Relation R belongs to BCNF if P -> Q is a trivial functional dependency and P is a superkey of R.

If the relation is in BCNF, it means that the redundancy based on functional dependencies has been removed, but some redundancy still exists.

Let’s see an example -

##End_TimePackage##G01G01##Gold10:30##10:15

# #ground	Begin_Time
07:00	09:00	Gold
10:00	##12:00		G01
##11:00	Bronze		G02
11:15	silver	##G02	08:00
09:00	Silver		##The above relationship is in 1NF, 2NF, and 3NF, but not in BCNF. The reason is as follows:

Functional dependency

{Package->Ground}

It has the decisive property Package on which Ground depends on neither the candidate key nor the Not a superset of candidate keys.

##Encapsulation

Ground##Silver##Bronze

##Gold	G01
G02
G01

##10:3011:00G02 10:1511:15##G02

ground	Begin_Time	End_Time
G01	07:00	09:00
G01	10:00	12:00
G01
08:00	09:00

Now the above table is in BCNF format.

The candidate keys for table are Package and Ground

## The candidate keys for table

are {Ground, Begin_Time } and {Ground, End_Time}Because we are in

relationship.

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