No tables have been defined.

How to fix

Ensure that you have at least one table defined.

{
  "datasets": [
    {
      "name": "CustomNames",
      "type": "List",
      "values": ["Alice", "Bob", "Charlie"]
    }
  ]
  // Missing "tables" array
}

Ensure that you have at least one table defined:

{
  "tables": [
    {
      "schema": "Person",
      "name": "Address",
      "columns": [
        {
          "name": "City",
          "deterministic": false,
          "maxLength": 15
        },
        {
          "name": "AddressLine1",
          "dataset": "AddressesUnique",
          "deterministic": false
        }
      ]
    }
  ],
  "datasets": [
    {
      "name": "CustomNames",
      "type": "List",
      "values": ["Alice", "Bob", "Charlie"]
    }
  ]
}