may also be english as a second+ language or just a frequent brainfart around pluralization, see the intro:
> This post explains what 1NF actually means and is useful for, and debunk a number of the misunderstandings.
> This post explains what 1NF actually means and is useful for, and debunk a number of the misunderstandings.
I have never seen terms like domain and attribute used as if they were plurals (the way "data" is), but even were that correct, "a domain have" would be contradictory, so I think it is just a linguistic quirk of the writer.