Conditions for transforming relational databases into equivalent tree databases

Determine the conditions under which a relational database can be transformed into an equivalent tree database, including conditions for transforming the relational schema into trees and for defining an equivalent tree-database instance for every consistent relational-database instance.

Background

The paper proposes using a tree database as an interface to relational data. The proposed transformation has two stages: convert a relational schema into a set of trees, and then construct an equivalent instance of the tree database from each consistent relational-database instance.

Although the paper gives preliminary ideas based on minimal covers and functional dependencies, it explicitly presents the general equivalence question as a larger unresolved question and describes implementation of the transformation as a long-term project.

References

The idea to use a tree database as an interface to a relational database requires to answer a larger question, namely: under what conditions can we transform a relational database to an `equivalent' tree database? To answer this question, we proceed in two steps as follows:

— Tree Databases  (2609.03538 - Spyratos, 3 Sep 2026) in Section 7, subsection “A tree database as an interface”