```json { "classifications": [ { "column": "country_id", "role": "identifier", "confidence": 1.0, "reason": "Primary key with unique values (251 distinct in 251 rows) used to identify each country" }, { "column": "name", "role": "attribute", "confidence": 0.95, "reason": "Descriptive country name for display; while unique, it's free-form text not used for joining" }, { "column": "code", "role": "identifier", "confidence": 0.85, "reason": "Country code (e.g., AD, AE) serves as an alternate key/identifier for joining or lookups" }, { "column": "continent", "role": "dimension", "confidence": 1.0, "reason": "Low-cardinality categorical field (6 values) used to group, filter, or slice data" }, { "column": "has_brewer", "role": "dimension", "confidence": 1.0, "reason": "Boolean flag (2 values) used to filter or segment countries by brewer presence" } ] } ```