{
  "schema": {
    "bsonType": "object",
    "required": ["user_id", "article_id"],
    "permission": {
      "read": true,
      "create": "auth.uid != null",
      "update": false,
      "delete": "doc.uid == auth.uid"
    },
    "properties": {
      "_id": {
        "description": "ID，系统自动生成"
      },
      "article_id": {
        "bsonType": "string",
        "description": "文章id，参考opendb-news-articles表",
        "foreignKey": "opendb-news-articles._id"
      },
      "user_id": {
        "bsonType": "string",
        "description": "收藏者id，参考uni-id-users表",
        "forceDefaultValue": {
          "$env": "uid"
        },
        "foreignKey": "uni-id-users._id"
      },
      "create_date": {
        "bsonType": "timestamp",
        "description": "收藏时间",
        "forceDefaultValue": {
          "$env": "now"
        }
      }
    }
  },
  "index": [{
    "IndexName": "article_user_",
    "MgoKeySchema": {
      "MgoIndexKeys": [{
          "Name": "article_id",
          "Direction": "1"
        },
        {
          "Name": "user_id",
          "Direction": "1"
        }
      ],
      "MgoIsUnique": true
    }
  }]
}