{
  "name": "acc_cdrs",
  "version": 2,
  "columns": [
    "id": {
      "type": "int",
      "default": null,
      "null": false
    },
    "start_time": {
      "type": "datetime",
      "default": "2000-01-01 00:00:00",
      "null": false
    },
    "end_time": {
      "type": "datetime",
      "default": "2000-01-01 00:00:00",
      "null": false
    },
    "duration": {
      "type": "double",
      "default": 0,
      "null": false
    }
  ]
}