The specific structure and presentation of it could be, and the items individually could be. There are some jurisdictions where a dataset as such rather than just the structure and presentation have legal protections, but those are slightly distinct from copyright AIUI, and as such I imagine you'd want a tailored license for that rather than GPL. They're called database rights.

The ODbL is a sharealike open license for datasets.

https://opendatacommons.org/licenses/odbl/

As in anything developed using it also becomes GPL?