Why is this table not normalized?

Question

I am taking a database course and I am studying table normalization.

Could anyone explain to me, why the second table in the first row on the right not normalized?

Answer 1

It is not normalized because
For a student who has signed for more than one course, the entries in the table will be:
23 Jake Smith CS101 B+
23 Jake Smith B102 C+
Clearly the data is being repeated(redundant data). It is leading to anomalies(insert, update, delete anomalies).
Ex:
When you have to change the name of a Student say Jake Smith, you have to modify all of the rows,this is called an update anomalie.

Normalization is used to avoid these kind of anomalies and redundant data storage.
The table on the right hand side in the second row handles this situation in a better way, as it stores id, name and DOB in a separate table, the edits can be made easily using id attribute on a single row.
There are several normal forms like 1NF, 2NF, 3NF etc. Each normal form has some constraints associated with it. Each Higher form being stricter than the previous one.