Dear Rene
Thank you for your reply, here is what I intend to do:
I want to create a TFile, which should organize experiments in a
hierarchical structure. The “employee” folder should contain references
to TTrees and some additional information as objects. The TTrees
themselfs containing the data will be stored in different TFiles.
Access to the TTrees should be handled from this main file.
The update frequency is low, e.g. hundred experiments per week each
containing about hundred TTrees.
Although some of your slides suggest MySQL as Run/File catalog for
the Event Store I must admit that I do not believe in RDBMS.
Browsing the book “The Object Data Standard: ODMG 3.0” from the
members of the ODMG, one can see that most classes described in the
book are already implemented in ROOT. One of the few classes missing
is class TTransaction {begin(), commit(), abort()}.
I have already started to implement this class in a way which is
sufficient
for my purposes, and it seems to work fine.
My main problem is to implement a hierarchical structure in the main
file which is not only browsable but also searchable.
Best regards
Christian
Rene Brun wrote:
> Hi Christian,
>
> It is difficult to give you an advice without knowing a more
> precise configuration and access patterns.
> What is the update frequency? one per millisecond, second, month ?
> What is the real population in each node?
>
> It is also not clear to me what are the operations you need to
> perform: in memory only, on disk only, on both.
>
> ROOT I/O is not an alternative to a pure conventional relational
> data base to describe eg, employee/organisation type of relations.
> May be a tool like MySQL is more adapted to this task.
>
> Rene Brun
>
> On Sun, 6 Jan 2002, cstrato@EUnet.at wrote:
>
> > Dear Rooters!
> >
> > Maybe you can give me some advice whether to use TFolder or TDirectory
> > when storing large amounts of TObjects in a TFile.
>
> >
> > Thank you in advance
> >
> > Best regards
> > Christian
> > ----------------------------------
> > C.h.r.i.s.t.i.a.n S.t.r.a.t.o.w.a
> > V.i.e.n.n.a, A.u.s.t.r.i.a
> >
> >
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