I searched Google for the definition of a single-table relational database and found nothing but redirection to other database models. What's up? Why is this concept confusing? Every relational database is also a single-table relational database. The key difference between a standard RDBMS presentation and its single-table presentation is that relationship management is in the data and not in a tool to manage tables.
As seen in the image above, the single-table form of the RDBMS is a pivot of a normal table. Each value is identified by location in TableID, ColumnID and RowID. Just a two-dimensional matrix of foreign keys. The value also needs to be typed, a function normally handled by the RDBMS table management tool (this may or may not require multiple value columns where only one location will be not null).
The single-table form of the database has unique advantages over standard table form. As shown, semantics is removed. Relations are handled by data description, not by a table tool. This makes the ontologies of relationships an input to the stored procedures that return data to various applications using the data. You can use hierarchical structure, graph database triplets or whatever. Of course, you can always pivot the tables back to their original form.
I have added four columns to the single-table presentation. The Language column allows table and column names to be presented in the language of choice. This allows the database to work in any language. EntryDate, IsActive and UserID allows edits and deletions (marked inactive, not removed) to be attributed to a user according to when the change was made. This makes the database recordings immutable on a field-by-field basis.
Am I missing something? Is there a hidden flaw I haven't encountered in 18 years? This is a serious question. I am working with an international association dedicated to working with engineers to build and control better heating and air-conditioning systems. Think climate change. They are looking to define a building data exchange standard and I think a single-table RDBMS will eliminate many of the challenges they face.