In this page you will see a basic database normalization example, transforming BCNF table into a 4NF one(s).
The next table is in the BCNF form, convert it to the 4th normal form.
|
language |
skill | Employee |
|
French |
electrical |
Jones |
|
German |
electrical |
Jones |
|
French |
mechanical |
Jones |
|
German |
mechanical |
Jones |
|
Spanish |
plumbing |
Smith |
The above table does not comply with the 4th normal form, because it has repetitions like this:
|
A |
X |
Jones |
|
B |
Y |
Jones |
So this data may be already in the table, which means that it’s repeated.
|
X |
B |
Jones |
|
Y |
A |
Jones |
To transform this into the 4th normal form (4NF) we must separate the original table into two tables like this:
|
skill |
employee |
|
electrical |
Jones |
|
mechanical |
Jones |
|
plumbing |
Smith |
And
|
language |
employee |
|
French |
Jones |
|
German |
Jones |
|
Spanish |
Smith |