This paper attempts to explain consequences of the relational calculus not allowing relations to be domains of relations, and to suggest a solution for the issue. On the example of SQL we describe the consequent problem of the multitude of different representations for relations; analyze in detail the disadvantages of the notions "TABLE" and "FOREIGN KEY"; and propose a complex solution which includes brand new data language, abandonment of tables as a representation for relations, and relatively small yet very significant alteration of the data storage concept, called "multitable index".