Sort is irrelevant, you can't have a coherent database without IDs cross-referencing entries between tables. If IDs were excluded it was deliberate. It'd be like trying to organize a library of books with no covers or titles.
I did a lot of DB development, architecture and optimization. This is 101.
I've also done my share of DB development. But nobody uses database software to analyse or store data from a scientific study. It would be a huge amount of overkill, and your statistical software wouldn't be able to read it. It would be like hiring a librarian to organise one Billy bookcase. Every study dataset I have ever seen is basically a spreadsheet, with records in the rows and variables in the columns. Indeed, a surprising number of studies are analyzed in Excel. PACE was analyzed with Stata, SAS, and SPSS, all of which assume the data is in a simple row/column form. The principle of using a key (such as a participant ID) to tie records together if they happen to get split across multiple files is of course the same as in database design, but this ought to be much simpler (not least because there shouldn't be multiple files!)
So if their data & data management processes are a mess - ie not up to basic standards, surely further undermines whole original trial as unreliable.
You could certainly make a good case for that. If the stories that they expect people to believe are true, then they are massively incompetent, to the point where they shouldn't be entrusted with anybody's data, let alone that of vulnerable patients. If not, then they are being wilfully obstructive. This whole story about "It would take a qualified statistician dozens of hours to identify the appropriate elements of the data" is almost certainly bollocks, relying on the judge not understanding the (very modest) technicalities of the process.
Also remember that PLoS ONE issued an Expression of Concern about the PACE "cost effectiveness" paper. Journals don't like doing that sort of thing, so they must have been unconvinced by the excuses of the authors. (They should, of course, have retracted the paper, in line with their stated policy of mandatory data sharing, but even the slap on the wrist in the form of an EoC won't have been done without a fair amount of failed negotiations with the authors.)
PS: As people here may or may not know, I'm not an ME patient, nor do I know (in real life) anyone who is. Over the past few years I've developed an interest in detecting and discussing (not to say "exposing") bad science, but I only got interested in this topic because for a while Jim Coyne was my PhD advisor and so PACE was often going past on my radar. Up to now I was always a little skeptical about some of the claims being made about the PACE researchers because of the obvious possibility for motivated reasoning, but the evidence that the researchers have at least something to hide certainly seems to be accumulating.