Is it possible to state that the scheme is normalized in 3FN?

Explaining the context

On the internet I found an example of a scheme described like this:

Account (num-account, descr-account, launch (NUM-lanc, typelanc, data-lanc, value-lanc)).

Notice that the way this scheme is, it is not normalized.

Now consider the following criteria:

  1. A counts and launch are groups of occurrence of the attributes in parentheses and to them juxtaposed;

  2. Underlined attributes are identifiers of the relationship to which they belong;

  3. num-lanc is dependent on num-conta, that is, in addition to num-lanc, it is necessary num-conta to identify a specific release;

  4. No it is necessary to save history, that is, the emergence of a pair in a-account and a-lanc equal to one already registered, replaces the registry.

Visto os critérios, agora devemos normalizar o esquema até a 3FN.

A possible alternative

Account (num-account, descr-account) and launch(numconta, NUM-lanc, data-lanc, value-lanc).

Doubt

Would the above example be normalized to 3FN?

Author: Comunidade, 2017-11-11

1 answers

Well let's go... seeing this possible alternative that you show in the question, I come to this conclusion...

Is in 1FN, as all fields contain only atomic and monovalued values, i.e. does not contain repeat groups.

Is also in 2FN, as there is no non-key attribute that is dependent on only a portion of the primary key.

And is in 3FN as well, as there are no non-key attributes being dependent on other non-key attributes key.

So I would state that it is in 3fn yes.

 3
Author: Lucimar, 2017-11-11 16:56:19