Database is [nothing but] an organized form of data

Question

I encountered a sentence

Database is nothing but an organized form of data [...].

and got confused by the part "nothing but".

1. What is it used for and what meaning does it convey here?

2. How correct is it to start a formal definition with "nothing but"?

3. How is it different from the next quote?

Database is an organized form of data [...].

I've seen a few sentences with this structure before. They were pretty logical, rather informal, and, I guess, "nothing but" meant "only" there.

Thank you in advance.

Answer 1

nothing but means a little more than "only".

Compare:

He's nothing but a scoundrel.

That could be paraphrased, "He has no virtues. He is is a scoundrel, plain and simple."

It reduces something to its essence (in the eyes of the speaker).

It can be used with hyperbole:

He bought a used car and it turned out to be nothing but a heap of rusty nuts and bolts.

So, to say that a database is "nothing but an organized form of data" ignores what are (in the speaker's eyes) irrelevant details, such as fault-tolerance, atomicity, adherence to standards, and so forth. The speaker is making a reductive assertion.

Answer 2

As Collins notes:

You use nothing but in front of a noun, an infinitive without 'to', or an '-ing' form to mean 'only'.

“Nothing but” is an expression used to emphasise the concept that the subject in question is characterized by one specific aspect.

It is often used also in book titles, see here