We have a number of workbooks that contain a lot of data. Each workbook has been separated into multiple identically-formatted worksheets based on geographical divisions (up to 16 separate worksheets in a workbook).

Until now we have been saving the data in "XML Spreadsheet" format. Each new version is checked into source control without merging because the internal formatting of the workbook causes major merge problems.

I am trying to save the workbooks as XML Data so that source control could save only the differences between versions. I have been successful at defining a schema to save a single worksheet. But as soon as a sequence or choice is added to allow mapping for a second worksheet I get the message that the XML maps cannot be exported. Also, if the schema reuses a complex element to describe the data row, Excel won't let the atomic elements to be mapped more than once.

After many different schema designs, I'm wondering if it is simply not possible. Does anyone have suggestions about how to approach this problem?

In the end, I would like a single XML document for each workbook containing the data from all of its worksheets, using the same element names for each worksheet.