[Zope] adding properties trough pythonscript

[massimop at users.berlios.de]

On Sun, 2004-10-17 at 22:44 +0200, Dieter Maurer wrote:
> massimop at users.berlios.de wrote at 2004-10-16 12:23 +0200:
> > ...
> >> Do not use "try: ... except:...". It is dangerous. It can easily
> >> lead to ZODB inconsistencies...
> >
> >not exactly good news to me....
> >
> >can you point out some document explaining this?
> 
> It follows from common sense (and therefore need no documentation ;-)
> 
>   Python's exceptions are abortive: as soon an exceptin is raise,
>   the normal flow of control is aborted.
> 
>   When you have modified persistent state before the exception occured,
>   the transaction must usually be aborted, to get the modifications
>   reverted. If instead, the transaction is committed, the (often)
>   partial change is made persistent.
> 
>   Usually, the Zope framework does this for you.
>   However, when you catch an exception, the framework may
>   not learn about the problem and commit rather than abort.
> 
>   As I wrote, this can easily lead to corruption of persistent
>   data.
yes, it looks sound...:)

thanks
massimo