[INFOD-WG] Minutes - INFOD conference call, Thursday, June 28 2007

[Dieter Gawlick]

Steve,

If I understand correctly your proposal, you promote to create a 
materialized view of the solution set as soon as a constraint is 
created. That is certainly another possible solution.

We may also like to add a statement concerning the event of a REPLACE 
statement containing constraints. We should say that all references 
marked DISABLED NEW will be discarded.

Dieter


Fisher, SM (Steve) wrote:
> Dieter,
>
> I still don't think it is a problem. The integrity rules are there avoid
> references to dead things. When C2 is created P will not be found. If C1
> is evaluated after t3 then if it had an explicit reference to P then P
> will be found otherwise not.
>
> I will take a read through the use case document to try to make this
> more concrete
>
> Steve
>
>   
>> -----Original Message-----
>> From: Dieter Gawlick [mailto:dieter.gawlick at oracle.com] 
>> Sent: 29 June 2007 20:27
>> To: Fisher, SM (Steve)
>> Cc: INFOD
>> Subject: Re: [INFOD-WG] Minutes - INFOD conference call, 
>> Thursday, June 28 2007
>>
>> Steve,
>>
>> The flag is not enough to do the required check. 
>>
>> Let us go through the following scenario:
>>
>>
>> *	The is a property instance P created at t1
>> *	There is a constraint C1 created at t2, P is in the 
>> solution set of C1
>> *	P is dropped with 'DISABLE NEW' at t3
>> *	There is another constraint C2 created a t4, P is in 
>> the solutions set of C2 - if the DISABLE NEW flag is discarded
>> *	t1 < t2 < t3 < t4
>> 	
>>
>> The DISABLE NEW flag is obviously not enough to determine, 
>> since P remains in the solution set of C1 but has to be 
>> excluded from the solution set of C2. So, one has to keep 
>> more information. There are certainly several obvious 
>> possibility. Adding VALID-FROM and VALID-TO seems to be the 
>> most sensible. 
>>
>> I am not sure whether this is strictly an implementation 
>> issue (just a recommendation) or whether we have to mandate 
>> it. I think we need to mandate it and add it to the 
>> specifications. Without additional information a GetMetaData 
>> request would not be able to answer the following question: 
>> What are the proper instances (and related entries) in the 
>> solution set of C1 or C2?
>>
>> Dieter
>>
>>
>> Fisher, SM (Steve) wrote: 
>>
>> 			*	The 'DISABLE NEW' support will 
>> remain and is 
>> 		considered to be useful. A possible 
>> implementation is to add 
>> 		a VALID-FROM and a VALID-TO field to (all?) 
>> registry elements 
>> 		and have a STILL-VALID and a TIME-OVERLAP check when 
>> 		constraints are evaluated
>> 		    
>>
>> 	
>> 	I don't understand this. It says in the spec "There is 
>> an optional flag
>> 	which can be set to "DISABLE NEW REFERENCES" which 
>> results in the entry
>> 	being dropped when the last reference to the entry has 
>> been removed"
>> 	
>> 	The entry is fully visible to anybody currently using 
>> it and remains
>> 	valid forever and fully functional as long as somebody 
>> has a reference
>> 	to it.
>> 	
>> 	Steve
>> 	  
>>
>>
>> -- 
>>
>>
>> Oracle Email Signature Logo
>> Dieter Gawlick | Architect | 650.506.8706
>> Oracle Server Technologies
>> 500 Oracle Parkway | Redwood Shores, CA 94065 
>>
>>     

-- 

Oracle Email Signature Logo
Dieter Gawlick | Architect | 650.506.8706
Oracle Server Technologies
500 Oracle Parkway | Redwood Shores, CA 94065
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