{
  "name": "::Demo",
  "connector": "trace",
  "table": { "name": "user_trace", "comment": "::Demo" },
  "columns": [
    { "label": "ID", "name": "id", "type": "ID" },
    {
      "label": "::SN",
      "name": "user_sn",
      "type": "string",
      "length": 42,
      "index": true
    },
    {
      "label": "::Uptime",
      "name": "uptime",
      "type": "datetime",
      "index": true
    },
    {
      "label": "::Action",
      "name": "action",
      "type": "enum",
      "option": ["进入", "离开"],
      "index": true
    }
  ],
  "indexes": [
    {
      "name": "user_sn_action_unique",
      "type": "unique",
      "columns": ["user_sn", "action"]
    }
  ]
}