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From Alexander Klimetschek <aklim...@day.com>
Subject Re: Repository migration
Date Mon, 01 Feb 2010 15:31:05 GMT
On Mon, Feb 1, 2010 at 16:04, Davide Maestroni
<davide.maestroni@gmail.com> wrote:
> thank you very much for your quick response. I understand that forcing
> constraints in node types is not advisable when I foresee evolving
> structures, though I would like to be able to 'fix' data automatically when,
> for example, an application requires specific properties to exist (even with
> default values).

You can use auto-created properties with default-values for that.
These should not be a blocker for future schema evolvement, if
residual property definitions are present, as they are only evaluated
upon creating the parent node.

Main problems with evolving schemas:
- node type inheritance changes
- mandatory properties that no longer should be mandatory
- new properties are added
- required primary types for child nodes

Therefore using those constraints should only be done when you are
sure that the model is complete and doesn't have to change in the
future. Or could be easily replaced by a completely new node type

> Now I have another question in mind: is there a way to intercept the data as
> soon as they are read from the persistent storage and before they are
> processed by Jackrabbit?

As I said, if you change node types, existing nodes won't necessarily
be re-evaluated until the next time data is written. There is no
constraint checking on reads (AFAIK).


Alexander Klimetschek

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