数据库归一化为3NF

Question

I have to normalize the data below to the 3NF, showing all the stages from UNF to 3NF.

I have made an attempt to it, but am not sure if its correct.

1NF

OwnerName(PK), OwnerAddress(PK), PhoneNo

OwnerName(PK), OwnerAddress(PK), PropertyRef(PK), NrOfBeds, Location, Facilities, WeeksAvailable

2NF

Owner(OwnerName(PK), OwnerAddress(PK), PhoneNo)

PropertyOwner (OwnerName(PK), OwnerAddress(PK), PropertyRef(PK))

Property (PropertyRef(PK), NrOfBeds, Location, Facilities, WeeksAvailable)

3NF

Owner(OwnerName(PK), OwnerAddress(PK), PhoneNo)

PropertyOwner (OwnerName(PK) , OwnerAddress(PK) , PropertyRef(PK)*)

Property (PropertyRef(PK), NrOfBeds, Location, Facilities)

WeeksAvailable(PropertyRef(PK)*, WeekNr(PK))

PropertyFacilities(PropertyRef(PK) , FacilityCode(PK) )

Facilities(FacilityCode(PK), Desc)

Answer 1

That looks like a reasonable first go. I'm a bit confused by all the PK notations. Does the Owner table really need the Address as part of the PK? Also, where did the PropertyOwner come from? What makes it different to Owner?

Best practice is to give each entity an Id - usually an auto-incrementing integer (IDENTITY in SQL Server), and use that as the PK. This means that if say an Owner changes their name the PK itself doesn't change.

I think some of the PKs you have a really FKs: FacilityCode in PropertyFacilities is really an FK; PropertyRef in that table is also as FK. The PK would be a unique identifier as above.

Does that make sense?