Answer: \DataSource\SubjectArea\YYYY\WW\FileData_YYYY_MM_DD.parquet

## Analysis of Folder Structure Options ### Key Requirements: - **Supports usage patterns**: Most queries filter by current year OR week - **Simplifies folder security**: Data secured by data source - **Minimizes query times**: Optimized for year/week filtering ### Evaluation of Options: **Option A (\DataSource\SubjectArea\YYYY\WW\FileData_YYYY_MM_DD.parquet)** - **RECOMMENDED** - **Security**: Places data source at the top level, enabling straightforward security policies at the data source level - **Query Performance**: Hierarchical structure (YYYY→WW) allows efficient partition pruning when filtering by year, and still supports week filtering through folder traversal - **Usage Pattern Support**: Organizes data logically by time granularity, supporting both year-based and week-based queries - **Best Practice**: Follows Azure's recommended hierarchical partitioning approach **Option B (\DataSource\SubjectArea\YYYY-WW\FileData_YYYY_MM_DD.parquet)** - **NOT OPTIMAL** - **Query Performance**: Combines year and week in single folder name, requiring full folder scan when filtering by week alone - **Security**: Similar to A, but query optimization is compromised - **Usage Pattern**: Less efficient for "year OR week" filtering requirement **Option C (DataSource\SubjectArea\WW\YYYY\FileData_YYYY_MM_DD.parquet)** - **NOT OPTIMAL** - **Security**: Data source not at top level, complicating security implementation - **Query Performance**: Week-first hierarchy is inefficient for year-based queries **Option D (\YYYY\WW\DataSource\SubjectArea\FileData_YYYY_MM_DD.parquet)** - **NOT OPTIMAL** - **Security**: Data source buried deep in hierarchy, making security management complex - **Query Performance**: Time-based partitioning is good, but security requirement is compromised **Option E (WW\YYYY\SubjectArea\DataSource\FileData_YYYY_MM_DD.parquet)** - **NOT OPTIMAL** - **Security**: Worst option for security implementation with data source at bottom - **Query Performance**: Week-first hierarchy is inefficient ### Why Option A is Optimal: 1. **Security Simplification**: Data source at root level enables straightforward access control policies 2. **Query Optimization**: Hierarchical time partitioning (Year→Week) enables efficient partition elimination 3. **Usage Pattern Alignment**: Supports both year-based and week-based filtering scenarios 4. **Azure Best Practices**: Aligns with Microsoft's recommended data lake organization patterns for time-series data Option A provides the best balance of security management simplicity and query performance optimization while fully supporting the specified usage patterns.