Kevin,
I don't know really. Probably it means attached XML stays as is but only the ToXML(...,lChangesOnly) outputs diffgram.
Cetin

>Thanks! This example is exactly what I was looking for.
>
>The help file says "Setting the IsDiffGram property does not actually
>alter the associated XML document."
>
>I'm not sure I understand this property. Can you elaborate?
>
>Thanks Cetin!
>
>
>
>
>>Yes and no. Depends on version. Under VFP9 you have the luxury doing this with XMLAdpater class. The diffgram I pasted is from VFP7. Here is a sample for VFP9 that both creates the diffgram (might be your COM1) and updates from XML diffgram (might be your COM2):
>>

>>LOCAL lcDiffXML
>>lcDiffXML = GetDiffGram() && COM1 creates diff.
>>UpdateFromDiffgram(m.lcDiffXML) && COM2 gets XML
>>
>>
>>PROCEDURE GetDiffGram
>>USE _samples+"\data\customer"
>>CURSORSETPROP("Buffering",5,'customer')
>>BROWSE TITLE "Modify on site 1"
>>
>>* Create diffgram xml
>>LOCAL lcChanges, oAdapter
>>oAdapter = CREATEOBJECT('xmlAdapter')
>>oAdapter.AddTableSchema('customer')
>>oAdapter.IsDiffgram = .T.
>>oAdapter.ToXML('lcChanges','',.f.,.t.,.t.)
>>* Closing data just for sampling
>>USE IN 'customer'
>>RETURN m.lcChanges
>>
>>PROCEDURE UpdateFromDiffgram(tcDiffGram)
>>LOCAL oAdapter
>>* just for sampling using a different alias
>>USE _samples+'data\customer' ALIAS myCustomer
>>* we don't want to save when we are sampling only
>>CURSORSETPROP("Buffering",5,'myCustomer')
>>BROWSE TITLE 'Before applying diffgram'
>>
>>oAdapter = CREATEOBJECT('xmlAdapter')
>>oAdapter.LoadXML(m.tcDiffGram,.f.)
>>oAdapter.Tables(1).Alias = 'myCustomer'
>>oAdapter.Tables(1).ApplyDiffgram()
>>BROWSE TITLE 'After applying diffgram'
>>

Too much hardcoding in there but this is a sample:)
>>PS: AFAIK you also work with .Net and you would like to know XMLAdapter is friendly with .Net datasets and diffgrams (also VFPOLEDB have as added support).
>>Cetin
>>
>>>Do I understand that I must store the changes back to the database myself? How is this
>>>done? There could be any number of records and field changed. Is there any way to do
>>>this automatically?
>>>
>>>
>>>
>>>>XmlUpdateGram() function creates an updategram (needs multilocks and buffering). That is it only includes updated/inserted/deleted records as updgram:before and after records. Suppose you updated customer table and changed company field, deleted ANATR and inserted NEWCUS. XmlUpdateGram('customer') produces an output like:
>>>>

>>>><?xml version = "1.0" encoding="Windows-1252" standalone="yes"?>
>>>><root xmlns:updg="urn:schemas-microsoft-com:xml-updategram">
>>>>	<updg:sync>
>>>>		<updg:before>
>>>>			<customer>
>>>>				<cust_id>ALFKI</cust_id>
>>>>				<company>Alfreds Futterkiste</company>
>>>>* other fields here
>>>>			</customer>
>>>>		</updg:before>
>>>>		<updg:after>
>>>>			<customer>
>>>>				<cust_id>ALFKI</cust_id>
>>>>				<company>Alfreds Futterkiste-Updated</company>
>>>>* other fields here
>>>>			</customer>
>>>>		</updg:after>
>>>>		<updg:before>
>>>>			<customer>
>>>>* all fields here - unmodified
>>>>			</customer>
>>>>		</updg:before>
>>>>		<updg:after/>
>>>>		<updg:before/>
>>>>		<updg:after>
>>>>			<customer>
>>>>				<cust_id>NEWCUS</cust_id>
>>>>* other fields here
>>>>			</customer>
>>>>		</updg:after>
>>>>	</updg:sync>
>>>></root>
>>>>

Instead of receiving the whole table diffgram approach only gets 'differences' IOW. On receving side you have to process this yourself however (ie: XMLDocument). VFP9 CA and XMLAdapter might help you to work with them in an easier way. Check www.prenia.com for samples.
>>>>Cetin
>>>>
>>>>
>>>>>The reason I'm using COM is because I will need to update the
>>>>>application piece by piece. I don't want everything compiled
>>>>>into one big EXE.
>>>>>
>>>>>Can you elaborate on the DiffGram option?
>>>>>
>>>>>
>>>>>
>>>>>>Hmm that in turn would bring up other questions. Ways to go are more than one and which one to choose depends. ie: One scenario:
>>>>>>
>>>>>>Instead of CursorToXml and XmlTocursor you might choose ADO and pass an ADO recordset instead.
>>>>>>Another one is to pass a diffgram instead of all rows using CursorToXML and XMLToCursor.
>>>>>>Yet another one might be passing just an array of records that are updated/added/deleted with flags.
>>>>>>
>>>>>>Actually first I would think of "do I really want to talk between COM objects or even do I want a single COM object in my application" - sounds like I don't like COM objects:) Really I don't, too much problems with them for me (call it DLL hell, security etc etc).
>>>>>>
>>>>>>If one of them can connect to data why would other one cannot and a need for 2 evils?
>>>>>>Cetin
>>>>>>
>>>>>>>Thanks. This brings up another question.
>>>>>>>
>>>>>>>I want to use CURSORTOXML() and XMLTOCURSOR() to pass data to and
>>>>>>>from COM objects.
>>>>>>>
>>>>>>>Once I make changes to data and convert it to XML, and after I use
>>>>>>>XMLTOCURSOR() to create a cursor, whats the best way to update the
>>>>>>>database?
>>>>>>>
>>>>>>>I am using a VFP database now, with possible plans later to convert
>>>>>>>to SQL Server.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>>For the 'nOutputFormat', 'nFlags', 'cSchemaName', 'cSchemaLocation', and 'cNameSpace'
>>>>>>>>>parameters, are there any standards as far as what settings I should use?
>>>>>>>>>
>>>>>>>>>I am only using the command to pass data back & forth between COM objects.
>>>>>>>>
>>>>>>>>If there were standards there wouldn't be flags;)
>>>>>>>>nOutputFormat: 2 or 3 are my favorites. More compact.
>>>>>>>>nFlags: 1 to make it compact.
>>>>>>>>For others it depends. Probably "1" inline schema would be good.
>>>>>>>>
>>>>>>>>With these settings:
>>>>>>>>CursorToXml('myAlias','myMemvar',2,1,0,"1")
>>>>>>>>would create a compact XML with inline schema and store in m.myMemvar and IMHO is good for your need.
>>>>>>>>Cetin