在node.js中从另一个模型引用一个模型

user465342 发表于 Dev

用户465342

我有两个模型问答。一个问题有很多答案，一个答案属于一个问题。

然后在“回送”中提供对答案的引用。我不知道的是，然后如何获得答案所属的问题的参考！？

module.exports = function(Answer) {

    console.log(ctx.instance.question)
    console.log(ctx.instance.question.points) // undefined


};

我可以得到看起来像是对该对象的引用……但是我不知道如何引用该对象的任何属性！

如何引用属于另一个模型的模型？

以下提供的问题和答案供参考。

{
  "name": "Question",
  "plural": "Questions",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "text": {
      "type": "string",
      "required": true
    },
    "points": {
      "type": "number",
      "required": true
    }
  },
  "validations": [],
  "relations": {
    "answers": {
      "type": "hasMany",
      "model": "Answer",
      "foreignKey": ""
    },
    "approval": {
      "type": "hasOne",
      "model": "Approval",
      "foreignKey": ""
    },
    "student": {
      "type": "belongsTo",
      "model": "Student",
      "foreignKey": ""
    }
  },
  "acls": [],
  "methods": {}
}

{
  "name": "Answer",
  "plural": "Answers",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "text": {
      "type": "string",
      "required": true
    }
  },
  "validations": [],
  "relations": {
    "question": {
      "type": "belongsTo",
      "model": "Question",
      "foreignKey": ""
    },
    "student": {
      "type": "belongsTo",
      "model": "Student",
      "foreignKey": ""
    },
    "approval": {
      "type": "belongsTo",
      "model": "Approval",
      "foreignKey": ""
    }
  },
  "acls": [],
  "methods": {}
}

乔丹·卡斯珀

我猜您提供的代码是common/model/answer.js基于文件的外观而来的，但是该文件是在应用程序设置期间执行的。上下文（ctx在您的示例中）将不存在。仅在远程挂接或其他此类操作期间提供上下文。因此，我将根据钩子为您提供答案，以根据Answer其ID查找，然后获取相关问题。此代码应放在您的common/model/answer.js文件中（在导出的包装函数中）：

Answer.afterRemote('findById', function(ctx, theAnswer, next) {
  theAnswer.question(function(err, question) { // this is an async DB call
    if (err) { return next(err); } // this would be bad...
    console.log(question);

    // You can then alter the question if necessary...
    question.viewCount++
    question.save(function(err) {
      if (err) {
        // an error here might be bad... maybe handle it better...
        return next(err);
      }
      // if get here things are good, so call next() to move on.
      next();
    });
  });
});