{
  "schema_version": 1,
  "kind": "WEB_TOOL_NESTED_PAYLOAD_SCHEMA",
  "schema_id": "orders-parent-child-v1",
  "revision": 1,
  "engine_route": "/csv-clean/",
  "tables": [
    {
      "table_id": "orders",
      "role": "parent",
      "key_columns": ["order_id"],
      "mappings": [
        {"column": "order_id", "path": "/id", "type": "string"},
        {"column": "note_kind", "path": "/note", "type": "null-or-empty-string", "null_policy": "manifest"}
      ]
    },
    {
      "table_id": "items",
      "role": "child",
      "key_columns": ["parent_id", "ordinal", "sku"],
      "parent_reference": {"parent_table_id": "orders", "parent_columns": ["order_id"], "child_columns": ["parent_id"]},
      "array_path": "/items",
      "mappings": [
        {"column": "parent_id", "path": "/parent_id", "type": "string"},
        {"column": "ordinal", "path": "/ordinal", "type": "integer"},
        {"column": "sku", "path": "/sku", "type": "string"},
        {"column": "qty", "path": "/qty", "type": "integer"}
      ]
    }
  ],
  "source_preservation": ["parent_id", "ordinal", "type", "null_policy"]
}