I’m sorry that I’m not very clear about what you said about using XML mapping and excel service.
We can create a map from a schema, and use that map to impot data, xml mapping can be used to make data more meaningful upon importing or exporting
data, here is an article about XML mappings, you can refer to it for more information:
To extend Excel Service with XML mapping, Excel Service will not support that, you can refer to the following link for more information:
Excel Services is a new server technology included in SharePoint Server 2007, it enables you to load, calculate and displayed excel workbook on SharePoint
2007, it makes excel workbooks easily to be reused and shared on SharePoint 2007 portals and dashboards, please refer to the following links for more information:
Excel Service overview: http://msdn.microsoft.com/en-us/library/ms546696(v=office.12).aspx
Excel Service Architecture: http://msdn.microsoft.com/en-us/library/ms582023(v=office.12).aspx
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