Dual belongsTo与loopback的关系

Question

我有一些想要建模的关系，

1. 邮件属于2个个人资料（发件人和收件人）
2. 注册包括个人资料和课程。

我尝试使用2个hasOne执行＃1但最终使用了Profile.messageId。

{
  "name": "Message",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "id": {
      "type": "number",
      "id": true,
      "required": true
    },
    "text": {
      "type": "string",
      "required": true
    },
    "created": {
      "type": "date",
      "required": true
    },
    "seen": {
      "type": "boolean",
      "required": true
    }
  },
  "validations": [],
  "relations": {
    "sender": {
      "type": "hasOne",
      "model": "Profile",
      "foreignKey": ""
    },
    "recipient": {
      "type": "hasOne",
      "model": "Profile",
      "foreignKey": ""
    }
  },
  "acls": [],
  "methods": []
}

同样的问题w /＃2 ...

{
  "name": "Enrollment",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "id": {
      "type": "number",
      "id": true,
      "required": true
    },
    "created": {
      "type": "date",
      "required": true
    },
    "currentPage": {
      "type": "string",
      "comments": "What page are they on in this curriculum?"
    }
  },
  "validations": [],
  "relations": {
    "curriculums": {
      "type": "hasOne",
      "model": "Curriculum",
      "foreignKey": ""
    },
    "profiles": {
      "type": "hasOne",
      "model": "Profile",
      "foreignKey": ""
    }
  },
  "acls": [],
  "methods": []
}