[cl-prevalence-devel] Removal of managed prevalence object does not delete corresponding non-id indexes' entries and duplicate index values allowed

[Sven Van Caekenberghe]

Nico,

On 18 Apr 2007, at 11:33, Nico de Jager wrote:


> When one deletes an object with tx-delete-object after creating an  
> index on a slot (other than id) of a managed prevalence class, the  
> corresponding index entry is not deleted. Because adding a new  
> object with tx-create-object appears to update all the indexes on  
> the class, one would expect tx-delete-object to also update the  
> indexes accordingly. Is this a bug or the intended behaviour?
>

The 'indexes on arbitrary slots' was contributed at one point. I do  
think the implementation was quite clear and simple.
But you are right, this is a bug (or oversight): when deleting an  
object, the index entries should be cleaned up.


> Also, shouldn't tx-create-object (or tx-change-object-slots) signal  
> a condition when the addition of an object or the change of a slot  
> results in duplicate slot values for an indexed slot?
>

Apart from indexes on keys (like ID), which are necessarily unique,  
indexes on arbitrary slots could theoretically be unique or not (as  
in SQL). The current implementation is using hashtables and is  
overwriting entries: so there too, there is a bug (or oversight):  
either we should enforce unique indexes by signalling errors, or we  
should allow multiple objects with the same indexed slot value, but  
then there should be a list as value there (and we have to manage all  
that correctly, esp. wrt. deleting objects).

What to you think ? How are you using this feature ?

So, thanks for reporting this problem. Do you feel like trying to fix  
this with a patch ?

Are there any other people on the list who would like to comment ?

Sven