---------- Forwarded message ---------- From: kelvin goodson <[EMAIL PROTECTED]> Date: Oct 12, 2007 2:40 PM Subject: Re: [SDO] merging Change Summaries To: Amita Vadhavkar <[EMAIL PROTECTED]>
On 12/10/2007, Amita Vadhavkar <[EMAIL PROTECTED]> wrote: > Hi, > > (DG = DataGraph, CS=ChangeSummary, DO = DataObject) a note on nomenclature, DG is a little ambiguous -- and could be taken to mean DataGraph or "data graph"; the first being an instance of the class so named, and the second being a term describing a single containment hierarchy of DataObject instances (the more general "graph" nature being bestowed by optional non-containment references). > > When checking randomly regarding change summary - came across some > points/questions - > > Did SDO always support (since 1.0) ChangeSummary on DG and DO level > property both? > No, initially Change Summary was only available on a DataGraph. Having added ChangeSummary capability to DataObject, there's not a lot that the DataGraph can do that can't be done by a suitably modelled DataObject. More background on this issue is that there have been lots of discussions about whether the DataGraph should also be a DataObject (using a Property of ChangeSummaryType to provide the Change Summary behaviour, and an open content Property to hold the root element name). These discussions are continuing in the 3.0 spec effort, but as it stands you have the option of choosing either the DataGraph or a suitably modelled DataObject to wrap a data graph. > Typically data travelling different tiers will be DGs (multi-root DO graph), > is it? In which > use case will a Data Access Service receive DOs with CS as property (not > contained in DG)? > One example use case is monitoring changes to a SOAP message without monitoring the Envelope. Other examples might be where a composite graph might be required, where the change monitoring information of each of the original data graphs is not lost. Of course in this use case the condition of not having overlapping change monitoring scopes must be preserved. > If there are DGs and DOs both come in to DAS, DAS will need ability to > support using > CS coming from both. Current DAS looks at DG only. > > Also simplistic approach is when a DO/DG has CS, apply it to DB one at a > time, do not attempt to merge these 2 and do not deal with any merge of CSs. > Will this suffice for most business cases or there will be need to merge and > send effective DG to DB? I guess this is something invalid as the current > SDO spec clear says against mixing CSs. indeed, if I understand this sentence correctly, the principle of non-overlapping change summaries prevents the situation. > > In short I am just trying to understand use cases of DO having CS as a > property and > whether there will be any changes in future in this support? Just to > understand > whether this is something that needs to be supported by DAS. If I understand correctly, the current spec effort does not intend to deprecate DataGraph, but simply to explore ways in which the story hangs together better. For example, if a DataGraph is a DataObject then it can be created with DataFactory. There are other similar synergies if this approach is adopted, but there are some detailed issues to be resolved before it's clear that this is the right approach. > > Got some old threads here, but nothing conclusive - > http://www.mail-archive.com/[email protected]/msg06642.html > http://www.mail-archive.com/[email protected]/msg17571.html > http://www.mail-archive.com/[email protected]/msg16800.html > > Regards, > Amita > > > On 10/10/07, kelvin goodson <[EMAIL PROTECTED]> wrote: > > > > Amita, > > > > The detail of the nature of the merge you want to perform is not > > completely clear, but you should be aware that inserting a DataObject > > of a Type that has a ChangeSummary property into a data graph wrapped > > in a DataGraph instance would violate the constraint that the scope of > > monitoring of two change summaries may not overlap. > > > > It would be interesting to know more about the issue you are trying to > > solve. It is possible to have a data graph (not DataGraph) with two > > or more change summaries in, by ensuring that the containment > > hierarchies of the DataObjects which contain the change summary > > properties do not overlap. That way you could assemble a composite > > graph carrying all the change summary info. > > > > There's no API for merging change summaries. The only way I can see > > might be possible for doing what you want would be something like 1) > > capture the change summary info for the DataObject in the DataGraph; > > reset the data in the DataGraph to its original state at the start of > > logging; merge the two graphs and "replay" the steps necessary to > > achieve the changes that had been made to the data that was originally > > in the DataGraph. > > > > Regards, Kelvin > > > > On 10/10/2007, Amita Vadhavkar <[EMAIL PROTECTED]> wrote: > > > When I have DO1 embedded in DataGraph and the DataGraph has change > summary > > > and I have DO2 with change summary property. > > > Is it possible to merge change summary of DO1(from data graph) with > change > > > summary from DO2 to form a final data graph with > > > DO3 with effective change summary? > > > > > > Regards, > > > Amita > > > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: > [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > >
