{
  "schema": {
    "bsonType": "object",
    "required": ["user_id", "article_id"],
    "properties": {
      "_id": {
        "description": "ID，系统自动生成"
      },
      "article_id": {
        "bsonType": "string",
        "description": "文章id，参考opendb-news-categories表"
      },
      "user_id": {
        "bsonType": "string",
        "description": "收藏者id，参考uni-id-users表"
      }
    }
  },
  "index": []
}