Re: list of items (recur-id is not CAP)

Arnaud Quillaud wrote:

>>If you sent:
>>
>>    QUERY:SELECT * FROM VEVENT
>>      WHERE DTSTART >='20000701T000000Z'
>>       AND DTSTART <='20000730T235959Z'
>>
>>You would get back VEVENTs with a DTSTART property value between
>>those two dates. If a recurring VEVENT existed and was daily starting
>>from DTSTART:19990101T000000Z, it  would not match the query, even
>>when one of its instances (RECURRENCE-ID) did match. The same is
>>    
>>
>
>Why ? Each of the instances of a recurring event has a DTSTART as far as I know.
>Why would we take into account only the first instance ?
>
The object that would be returned with a RECURRENCE-ID as shown in the
CAP QUERY example would return:

    VEVENT:

	DTSTART:19990101T000000Z
	RECURRENCE-ID: ...something that matched....

So the DTSTART still does not match, however the RECURRENCE-ID
that is calculated from EXPAND:TRUE does match.

When expanding an existing recurring object, you do not
modify the DTSTART value, you add a RECURRENCE-ID property
to be the effective start time of the Nth instance(s) that
match.


>>true if the VEVENT had a RDATE:20000702T000000Z, as you did not
>>query for RDATE, it would not match as RDATE is not DTSTART.
>>
>>The DTSTART value only matches the RECURRENCE-ID on the first instance
>>of a repeating object. If you query for DTSTART values, that 
>>is what you 
>>will get.
>>If you query for RECURRENCE-ID values, then you get any VEVENT that
>>has an effective instance start time that matches that value 
>>(somehow stored
>>or computed).
>>    
>>
>
>That is true only if the RECURRENCE-ID of the instance matches the DTSTART of this instance.
>
The first instance always matches the DTSTART value, else you could 
never compute
the second.

And 2445:

   The "DTSTART" property for a "VEVENT" specifies the inclusive start
   of the event. For recurring events, it also specifies the very first
   instance in the recurrence set.

>If this instance was originally:
> 
>RECURRENCE-ID:20000729T000000Z
>DTSTART:20000729T000000Z
>
> but the DTSTART is moved to 20000802T000000Z
>
>we end up with
>
>RECURRENCE-ID:20000729T000000Z
>DTSTART:20000802T000000Z
>
The 1st instance can not be less than the DTSTART value as 2445 mandates
that DTSTART is the first instance.

>If the "Query by Date-Time range" in the CAP example is done using the RECURRENCE-ID, this particular instance will be returned when it actually doesn't belong to that range.
>

You example was not valid.

>>All objects with an RRULE or RDATE property values have virtual
>>RECURRENCE-ID's even when an RECURRENCE-ID was
>>not explicitly sent or stored in the object.
>>
>>What do you think you would get back if EXPAND:FALSE were in
>>the CAP example?
>>    
>>
>
>My understanding is that we would return any event object that has at least one instance that matches the filter (whether it is RECURRENCE-ID or DTSTART).
>So for recurring event, we would return the MASTER event (the one containing RRULE/RDATE) and all its exceptions if there are any.
>
If you have EXPAND:TRUE, and query for RECURRENCE-ID, then ALL matching
VEVENTs that contain any RRULE  or RDATE would also contain a calculated
RECURRENCE-ID. Without the RECURRENCE-ID in a returned object that
also contains an RRULE or RDATE, then that object  returned is 
specifying a set of
UNexpaned instances. So no, you would not get back the master object 
that contained
unexpanded instances.

If you have EXPAND:FALSE and query for RECURRENCE-ID, you will get
back one object without any RECURRENCE-ID, which if expanded would match.

If you have EXPAND:TRUE and query for DTSTART, you will only get
objects that have a DTSTART value in that range.

If you have EXPAND:FALSE and query for DTSTART, you will only get
objects that have a DTSTART value in that range.

>If we take a daily VEVENT starting  from DTSTART:19990101T000000Z and recurring forever, it would be a match even though the DTSTART of this master event is not in the range.
>So we would get back:
>
>BEGIN:VEVENT
>DTSTART:19990101T000000Z
>RRULE:FREQ=DAILY
>...
>  
>
Again, DTSTART is not modified, only RECURRENCE-ID is added to the
returned object(s) in EXPAND:TRUE.

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