There is a db-relation called "relationship" and one called "friendship".
Before 1.10 I thought they were the same thing.

The relationship is manipulated in VVE using the "Person relationship" and friendship by "person relationship database" function with a Friendship string attached.

Is there a breakdown somewhere that explain when and for what these are supposed to be used?
I assume relationship is love and friendship is non romantic friendship?

I don't know the technicals but from playing I notice that friendship increases by asking them questions,doing the "Do you need help with anything?" questlines. Realtionship increases by dating and sexual interactions in general.