Re: Add-if-not-present

[masarati@aero.polimi.it]

>> I need to implement a modify operation whose semantics is "add if not
>> present", an add that only takes place if that attribute is not yet
>> present in the entry.
>>
>> I need it as an internal operation, so right now I wouldn't bother
>> formalizing it as an extension of the semantics of the modify operation.
>> Something like the SLAP_MOD_SOFTADD, which in turn consists in adding an
>> attribute value only if that value is not already present.
>>
>> I'd introduce a SLAP_MOD_ADD_IF_NOT_PRESENT flag and add code to support
>> it in all (well, most) backends/overlays that need to muck with modify
>> operation type.
>>
>> Comments?  Objections?  p.
>
> It might be a good idea to have a SOFTDEL as well; both are useful for
> declarative modifications of data.  Think of them in terms of:
>
> Soft Add: The attribute shall contain at least these values, but might
> have others
> Soft Del: The attribute shall contain none of these values, but might have
> others
>
> Ideally as modify sub-operations.

I'm not sure I understand how SOFTDEL differs from LDAP_MOD_DELETE.  Do
you mean that values listed in SOFTDEL will be deleted if they exist, or
otherwise ignored?

p.