How to merge a complicated mess

[Harry Putnam]

Harvey Chapman <hchapman-hg at 3gfp.com> writes:

[...]

Harry wrote:

>> All I can think of is having to do it all by hand which sounds like
>> a lot of time and effort.  And maybe not worth it

Harvey responded:

> Try pulling them into one repo and find yourself a nice graphical
> merge tool for your OS.

I'm not sure I understand why a graphical merge tool would be good.
I've used emacs ediff, vimdiff amd linux/unix diff.  But like I
mentioned.. I've not done serious merging with any of them.

Harvey wrote:

> Or… perhaps you need a database and not a version control system, or
> some combination of the two.

That comment zipped right over my head.  I have no practical knowledge
of databases'.  If you have the time, can you explain in some detail
what you mean there?