[GNC] Convert xml <-> sqlite on command line

[gnucash at 4forl1st5.slmail.me]

On Sunday, October 6th, 2024 at 23:26, Michael or Penny Novack via gnucash-user <gnucash-user at gnucash.org> wrote:
> 
> On 10/5/2024 5:18 PM, Eberhard Beilharz wrote:
> 
> > Hi,
> > is there a way to convert a Gnucash file in XML format to SQLite
> > format on the command line and the reverse?
> > I know I can do Save As in the Gnucash UI, but I would like to do it
> > from the command line so that I can automate it.
> > Thanks,
> > Eberhard

I am not aware of any existing tools that do that - in either
direction.

Back in the day, ..., when files were saved, by default, with a 
dot-xac extension, it might have been really simple to do it
using GnuCash, from the command line, in that much/most of the 
functionality inside the application was coded in Guile/Scheme 
and so you could load the "GnuCash library" into, and do some 
basic stuff inside, a Guile interpreter, but I'm guessing that 
may no longer be an option for you, as there's been a lot of C++ 
added over the years (and a lot of C "upgraded" to C++) although 
one of the Devs might know if enough of the Guile library routines
are still/now in there, and accessible.

Then again, the ability to talk to a "database backend" itself 
is "fairly recent", at least in geological time spans, so maybe 
there are no Guile mappings for the "export to SQL" capability, 
in which case you are looking at something like an XSLT transform 
to go in the 

 xml -> sqlite

direction, and some sqlite parsing tool/library for the other
direction.

The "trick" will be im mimicing GnuCash's internal data structures,
so that you don't lose anything (or maybe even add something!) 
across the transformations. 

As Michael D Novack suggests though, it should be do-able, given
enough time and effort.