[SDO] merging Change Summaries

[Amita Vadhavkar <am...@gmail.com>]

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

Fwd: [SDO] merging Change Summaries

[Amita Vadhavkar <am...@gmail.com>]

---------- Forwarded message ----------
From: kelvin goodson <ke...@thegoodsons.org.uk>
Date: Oct 12, 2007 2:40 PM
Subject: Re: [SDO] merging Change Summaries
To: Amita Vadhavkar <am...@gmail.com>

On 12/10/2007, Amita Vadhavkar <am...@gmail.com> 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/tuscany-dev@ws.apache.org/msg06642.html
> http://www.mail-archive.com/tuscany-dev@ws.apache.org/msg17571.html
> http://www.mail-archive.com/tuscany-dev@ws.apache.org/msg16800.html
>
> Regards,
> Amita
>
>
> On 10/10/07, kelvin goodson <ke...@gmail.com> 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 <am...@gmail.com> 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:
> tuscany-dev-unsubscribe@ws.apache.org
> > For additional commands, e-mail: tuscany-dev-help@ws.apache.org
> >
> >
>
>

Re: [SDO] merging Change Summaries

[Amita Vadhavkar <am...@gmail.com>]

Hi,

(DG = DataGraph, CS=ChangeSummary, DO = DataObject)

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?

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)?

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.

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.

Got some old threads here, but nothing conclusive -
http://www.mail-archive.com/tuscany-dev@ws.apache.org/msg06642.html
http://www.mail-archive.com/tuscany-dev@ws.apache.org/msg17571.html
http://www.mail-archive.com/tuscany-dev@ws.apache.org/msg16800.html

Regards,
Amita

On 10/10/07, kelvin goodson <ke...@gmail.com> 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 <am...@gmail.com> 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: tuscany-dev-unsubscribe@ws.apache.org
> For additional commands, e-mail: tuscany-dev-help@ws.apache.org
>
>

Re: [SDO] merging Change Summaries

[kelvin goodson <ke...@gmail.com>]

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 <am...@gmail.com> 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
>

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