Re: how to suppress carefully a recursive tree

"fj" <francois.jacq_at_irsn.fr> wrote in message news:4e22c235-3e07-4fcd-a9d1-f3362ea99239_at_v46g2000hsv.googlegroups.com...
> On 23 jan, 01:12, David BL <davi..._at_iinet.net.au> wrote:
> > On Jan 23, 1:10 am, fj <francois.j..._at_irsn.fr> wrote:
> >
> > > On 22 jan, 15:52, Jan Hidders <hidd..._at_gmail.com> wrote:
> >
> > > > On 22 jan, 12:04, fj <francois.j..._at_irsn.fr> wrote:
> >
> > > > > I know how to suppress a normal tree but I meet the following kind
of
> > > > > situation :
> >
> > > > I'm guessing that when you say "suppress" you mean "represent in a
> > > > database". Correct?
> >
> > > No : I want to destroy, remove, kill ... a part of the data (a
> > > complete tree or just a branch), but without destroying data shared by
> > > other trees or branches.
> >
> > Would the mark and sweep algorithm suit you purposes?
>
> No
>
> the mark and sweep algorithm needs to know all the tree roots in order
> to mark all the used objects.
>
> In my example I indicates that the node b3 belongs to the root r2
> just for information to explain the storage count. But the deletion
> routine I want to write just receives "r1" as argument, nothing else.
> It does not know that r2 exists too ... It is just able to detect the
> existence of other objects via the storage count of b3 which is a
> little bit too high for being just referenced by r1 !
>

How is the tree represented? If it's in the usual child-parent relationship, then you will have to traverse the sub tree in order to locate all its nodes.

If it's in the nested set representation, then there is a simple query to return every node in the subtree. Received on Wed Jan 23 2008 - 12:02:52 CET