Add a link to the dataset on the article

In our journal we often have dataset related to an article that are published in other system.
So we have a DOI for the dataset that we would like to associate with the article in order to display this DOI in the article view.
I know how to modify the front office template, but I don’t really know if I can use an existing field in the data model to store the DOI of the dataset or if I need to create a new one.

Application Version - e.g., OJS 3.1.2:
OJS 3.3.0.8