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If $Spec(O_K)$ is an open subscheme of Is there a connected non-affine scheme $S$, is it equal to S$ such that it is the union of rings of integers of number fields?

I was woolgathering about the notion of a scheme, and it occurred to me that I know of no non-affine scheme $S$ that has as an open subscheme of it is the ring union of integers $O_K$ Spec(O_K)$'s of some number field $K$.K$ (I allow $K$ to vary - so that $S$ might be $Spec(O_K)\cup Spec(O_L)$ for example).

It would an interesting notion if one could patch rings of integers together to form some non-affine $1$-dimensional normal scheme $S$. The fact that I've never seen an example makes me think it's impossible.

Question

Is there a connected non-affine scheme $S$ such that it true is the union of open subschemes of it that are $Spec$'s of rings of integers of number fields?

More pointedly, if $Spec(O_K)$ (the ring of integers of some number field $K$) is an open subscheme of a normal scheme $S$ then it is it equal to it?
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I was woolgathering about the notion of a scheme, and it occurred to me that I know of no scheme $S$ that has as an open subscheme of it the ring of integers $O_K$ of some number field $K$.

It would be an interesting notion if one could patch rings of integers together to form some non-affine $1$-dimensional normal scheme $S$. The fact that I've never seen an example makes me think it's impossible.

Question

Is it true that if $Spec(O_K)$ (the ring of integers of some number field $K$) is an open subscheme of a scheme $S$ then it is equal to it?
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If $Spec(O_K)$ is an open subscheme of a scheme $S$, is it equal to it?

I was woolgathering about the notion of a scheme, and it occurred to me that I know of no scheme $S$ that has an open subscheme of it the ring of integers $O_K$ of some number field $K$.

It would be interesting notion if one could patch rings of integers together to form some non-affine $1$-dimensional normal scheme $S$. The fact that I've never seen an example makes me think it's impossible.

Question

Is it true that if $Spec(O_K)$ (the ring of integers of some number field $K$) is an open subscheme of a scheme $S$ then it is equal to it?