>Let's call this category \$$\mathcal{D}\$$. A functor \$$F: \mathcal{C} \to \mathbf{Set} \$$ is a database consisting of a set of Germans.

Is this correct? Shouldn't it be "A functor \$$F: \mathcal{D} \to \mathbf{Set} \$$ is a database consisting of a set of Germans"?