Logical Table Sources & Fragmentation
Explain how fragmentation content rules split logical fact/dimension data across multiple physical sources (e.g., by region or date range) for query efficiency.
Fragmentation is aggregate navigation's close cousin, but instead of splitting data by *grain* (detail vs. summary), it splits data by *content* — different subsets of the same logical entity living in different physical tables or databases, often for historical, regulatory, or partitioning reasons. This is a more advanced RPD topic that separates intermediate from senior candidates.
It's like a library that keeps this year's newspapers at the front desk for quick access but ships everything older than a year to an off-site archive — a librarian (the BI Server) knows exactly where to look based on the date you ask for, and can even combine both sources if your request spans the boundary.