def _intermediary_to_dot(tables, relationships):
    """ Returns the dot source representing the database in a string. """
    t = '\n'.join(t.to_dot() for t in tables)
    r = '\n'.join(r.to_dot() for r in relationships)
    return '{}\n{}\n{}\n}}'.format(GRAPH_BEGINNING, t, r)
Returns the dot source representing the database in a string.