1NF
Since the column Address
has non-atomic values
, the table is not in 1NF. Thus the table will be broken down into R1 and R2.
Based on the data in the above table, we see that the Address
is derived from the combination of Pid and Mid
. Thus in R1, we will have Primary Key(Pid, Mid)
and Address. The Composite Primary Key (Pid, Mid, Address)
will uniquely identify each tuple.
R1
Pid | Mid | Address |
---|---|---|
1 | 101 | Ktm |
1 | 101 | Bkt |
2 | 101 | Bkt |
1 | 102 | Ltp |
1 | 102 | Ktm |
3 | 105 | Brt |
3 | 105 | Bkt |
4 | 105 | Ktm |
In R2, we will have the remaining columns.
R2
Pid | Pname | Price | Mid | Mname | Phone |
---|---|---|---|---|---|
1 | ABC | 1000 | 101 | EFG | 4412 |
2 | XYZ | 2000 | 101 | EFG | 4561 |
1 | ABC | 3000 | 102 | MNP | 2341 |
3 | ABC | 1000 | 105 | IBD | 2169 |
4 | XYZ | 1000 | 105 | IBD | 6635 |
R1 and R2 are in 1NF.
2NF
R1 is already in 2NF because there is no non-prime attribute and hence there are no partial dependencies
.
In R2 however, there are a few partial dependencies
.
is a partial dependency because Pname can be derived from only Pid.
Similarly,
is a partial dependency because Mname can be derived from only Mid.
To convert table R2 into 2NF, we break down the table into R3, R4, and R5.
R3
Pid | Pname |
---|---|
1 | ABC |
2 | XYZ |
3 | ABC |
4 | XYZ |
R4
Mid | Mname |
---|---|
101 | EFG |
102 | MNP |
105 | IBD |
R5
Pid | Mid | Price | Phone |
---|---|---|---|
1 | 101 | 1000 | 4412 |
2 | 101 | 2000 | 4561 |
1 | 102 | 3000 | 2341 |
3 | 105 | 1000 | 2169 |
4 | 105 | 1000 | 6635 |
Now, the following dependencies occur:
As we can see there aren't any partial dependencies now, we can confirm that the tables R1, R3, R4 and R5 are in Second Normal Form(2NF).
3NF
Table R1 is in 3NF because there isn't any Transitive Dependency
.
Table R3 is in 3NF because there isn't any Transitive Dependency
.
Table R4 is in 3NF because there isn't any Transitive Dependency
.
Similarly, there isn't any Transitive Dependency
in R5. Thus we can confirm that tables R1, R3, R4 and R5 are in Third Normal Form(3NF).
The question does not mention up to which level we need to normalize the table. In most cases, tables in 3NF are safe enough to prevent all kinds of database anomalies. Thus we leave them to 3NF.