```json { "proposals": [ { "join_class": "currency", "column": "Zomato Restaurant Dataset.Currency", "kind": "external_candidate", "entry_id": null, "name": "European Central Bank daily reference rates (all currencies)", "probable_url": "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.zip", "license_expectation": "Public domain / ECB terms of use (free for non-commercial and commercial use with attribution)", "join_story": "Joining daily exchange rates would let this restaurant dataset express all costs in a common currency, making price comparisons meaningful across the seventeen countries represented.", "teaches": "Whether a restaurant is genuinely expensive for its market or just appears so because of currency differences — revealing true purchasing-power-adjusted pricing patterns." }, { "join_class": "geo_state", "column": "Zomato Restaurant Dataset.City", "kind": "external_candidate", "entry_id": null, "name": "GeoNames cities database", "probable_url": "https://download.geonames.org/export/dump/cities15000.zip", "license_expectation": "Creative Commons Attribution 4.0", "join_story": "Joining city-to-country and city-to-region mappings would enrich the geographic hierarchy, enabling state or province-level aggregation that the dataset currently lacks despite spanning multiple countries.", "teaches": "Which regions within countries show the highest restaurant density or rating patterns — moving beyond city-level to understand broader geographic trends." } ] } ```