How to update the database
Export the exceldatabase to xml (xsd Format)
Put all these files in to a folder on the server where the zope server is running and where zope has the rights to read theses files
Create an config-file:
<xml>
<pathToFolder path="path/to/the/folder">
<db container="name of the xml tag which describes an dataset"
identifier="fieldname which identifies a data set uniquely"/>
<db .../>
<db..../>
</xml>