2.1.768 Part 4 Section 184.108.40.206, cacheSource (PivotCache Source Description)
a. The standard says that data source information is retrieved with the connectionId attribute.
Office only uses the connectionId attribute for external data sources.
b. The standard states that the connectionId attribute is the index to the workbook connection.
Office requires that the connectionId attribute be the unique ID of the workbook connection.
c. The standard does not place any restrictions on the value for the connectionId attribute.
In Office, the connectionId attribute specifies the unique identifier of the workbook connection. When the cache type is set to External, this value shall be greater than 0 and shall be equal to id in one of the connection elements.
d. The standard does not define any required schema based on the value of the type attribute.
Office requires that if this value is worksheet, a child element worksheetSource shall be present. If this value is consolidation, a child element consolidation shall be present.