A database-theoretic variant of Formal Concept Analysis (FCA) defines the concept lattice of a relational structure. The concept lattice naturally extends to a relational concept algebra; this further deepens the connection between FCA and database theory. It seems possible to axiomatically characterize concept lattices of relational structures using the additional concept operations; partial results have been presented in recent work. This requires to be precise about the underlying data model, as even small details can affect the axiomatization. In this article, we give an up-to-date presentation of our primary relational data model.