[Zope] one 'document' in many 'folders'

[Stefan Franke]

Jim Fulton wrote:
	> Sorry you didn't get an answer.  There is no problem with
creating 
	> acyclic or cyclic graph constructors in the, uh, object
hierarchy, 
	> which BTW, need not be a hierarchy. :)

Not too long ago I experimented a little with cyclic structures
inside Zope's database. One thing I noticed was, that the copy
support failed with tracebacks like this:

Traceback (innermost last):
  File D:\Programme\zope\koelnzope\lib\python\ZPublisher\Publish.py,
line 877, in publish_module
  File D:\Programme\zope\koelnzope\lib\python\ZPublisher\Publish.py,
line 590, in publish
    (Info: /BLS/1000/ADV-Angelegenheiten/manage_pasteObjects)
  File D:\Programme\zope\koelnzope\lib\python\OFS\CopySupport.py, line
176, in manage_pasteObjects
    (Object: Navigation)
  File D:\Programme\zope\koelnzope\lib\python\OFS\CopySupport.py, line
361, in _getCopy
    (Object: Navigation)
  File D:\Programme\zope\koelnzope\lib\python\BoboPOS\PickleJar.py, line
327, in export_file
  File D:\Programme\zope\koelnzope\lib\python\BoboPOS\SimpleDB.py, line
958, in exportoid
ExportError: Object 184337 references itself

This led me to the conclusion to better leave my hands
off non-hierarchic data structures which differ from those
created by the management interface itself.

	>> Would also like to hear more about this...
	> Like what? :)

More or less simple answers like "this is ok and this
is not", or "you can store any complex Python data
structure inside the DB, but in conjunction with the
management interface, you get the following drawbacks.."

I'm still a quite unclear about the object management
in the database itself and the management layer Zope
adds. 
But maybe I just have to read the docs harder ;-)

Stefan


>