There’s a vigorous discussion of TransRelational over on Alf Pedersen’s blog, although it’s completely polluted by some usual-suspects flame war BS.
Alf did poke through the dreck, however, to make a reasonable challenge, which can be paraphrased as:
OK. Suppose you’re right that no implementation has ever provided evidence of TransRelational’s usefulness for building a True Relational DBMS. It’s still theoretically fascinating.
My response was as follows:
Here are two big problems with TransRelational that are perfectly theoretical.
First, it assumes that values can be concisely stated, presumably as numbers or character strings. That isn’t a good match to complex datatypes such as, say, documents that should be full-text indexed.
Second, it assumes that there’s a natural sort order. That could be a bit of a problem even for, say, geospatial. One would think there’s a workaround in the geospatial case, e.g. like Oracle’s old hhencode. But hhencode was a fiasco, I think because it didn’t actually measure proximity very effectively.
Admittedly, both of my objections also apply to good old b-trees. Still, they speak against the potential of a TransRelational implementation to achieve the kind of generality I think modern applications do and will increasingly demand.
Basically, I think a “True Relational” DBMS that was only useful for columns with natural sort orders wouldn’t be particularly interesting. And “The Third Manifesto” notwithstanding, that’s the only kind anybody seems to have even hinted at trying to bring to market.