```json { "table_name": "neal_reading_groups", "primary_key": "reading_id,rank", "candidates": [ { "rank": 0, "partition_key": "reading_id", "partition_key_label": "primary_identifier", "partition_key_reasoning": "RPUV=3.67 is in the ideal range (2-100), uniqueness=0.273 indicates good cardinality with 60 distinct readings. Top 3 coverage=5.45% shows excellent distribution. Semantically, reading_id is the primary entity organizing these grouped readings.", "clustering_key": null, "clustering_key_label": null, "clustering_key_reasoning": "Dimension tables typically do not require clustering. The rank column provides ordering within each reading_id group but is part of the composite primary key rather than a separate clustering dimension.", "world_line": null, "session_column": null, "confidence": "HIGH", "notes": "This is a dimension table storing grouped reading data with a composite primary key (reading_id, rank). Each reading_id has multiple ranked entries (typically 4 rows per reading based on rank values 1-4). The table stores label-value pairs with associated metadata. No clustering key is needed as dimension tables are typically small lookup tables." } ] } ```