Re: [ROOT] TFolder or TDirectory?

From: Christian Holm Christensen (cholm@hehi03.nbi.dk)
Date: Tue Jan 15 2002 - 14:44:10 MET


Hi Rene, 

On Mon, 14 Jan 2002 21:45:12 +0100 (MET)
Rene Brun <brun@pcbrun.cern.ch> wrote
concerning "Re: [ROOT] TFolder or TDirectory?":
> OK, you simply want a translation mechanism from SQL format to TTree::Draw
> format. You can do this by extending TTreeFormula to support an SQL query.
> If you provide the function and test it on multiplatforms, I will 
> include it in the source.

It's quite a big endevour, 'cause you have to allow for things like 

  SELECT <member> FROM <branch> WHERE <expression> 
  SELECT <branch1>.<member> FROM <branch1>,<branch2> 
    WHERE <some expression envovling members of branch1 and branch2>

not to mention 

  INSERT INTO <branch> (<member list) VALUES (<value list>) 
  UPDATE TABLE <branch> SET <member>=<value> 
  
Ofcourse one can start with simle SELECTs, and just give errors in
other cases.  Anyway, I'm afraid it requires a lot of work, which I
can't do right now - sorry.  I did start something, but never got very
far, 'cause I realised just how much work it would take.  Perhaps at
some later point. 

Yours, 

Christian Holm Christensen -------------------------------------------
Address: Sankt Hansgade 23, 1. th.           Phone:  (+45) 35 35 96 91 
         DK-2200 Copenhagen N                Cell:   (+45) 28 82 16 23
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Email:   cholm@nbi.dk                        Web:    www.nbi.dk/~cholm



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