dbinfer-amazon: refresh ER schema diagram + dataset card

dbinfer-amazon/README.md

@@ -13,7 +13,7 @@ Amazon from the 4DBInfer benchmark: a large product-review dataset linking users
 
 ![schema diagram](schema.svg)
 
-Open [`schema.svg`](schema.svg) for a zoomable view: each table lists all of its columns and types, with primary keys, foreign keys, and the foreign-key edges between tables.
+Open [`schema.svg`](schema.svg) for a zoomable view: each table shows its columns and types and its row count, with primary keys, foreign keys, time columns, and the foreign-key relationships (crow's-foot notation) between tables.
 
 Splits: validation `2016-01-03 00:00:00`, test `2016-01-04 00:00:00` (rows up to a split's timestamp are the inputs for that split).
 
@@ -21,9 +21,9 @@ Splits: validation `2016-01-03 00:00:00`, test `2016-01-04 00:00:00` (rows up to
 
 | task | kind | type | description |
 |---|---|---|---|
-| `rating` | external | multiclass_classification | Predict the star rating a user gives a product. |
-| `purchase` | external | multiclass_classification | Predict whether a user purchases a product. |
 | `churn` | external | binary_classification | Predict whether a user churns (stops purchasing). |
+| `purchase` | external | multiclass_classification | Predict whether a user purchases a product. |
+| `rating` | external | multiclass_classification | Predict the star rating a user gives a product. |
 
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