hasOne relation and Angular

[Jonathan Carlson]

Having a bit of trouble getting the hasOne relation working within Angular.

I'm building a survey app, with questions that can be reusable amongst surveys. I have two question models to represent this: SurveyQuestion and Question.

SurveyQuestion has a hasOne relation to Question

Question has two properties: text (the question text) and type (checkbox, radio button, text input, etc.)

Here's the JSON (removed parts that aren't applicable):

// SurveyQuestion Model
{

  "name": "SurveyQuestion",

  "plural": "surveyquestions",

  "base": "PersistedModel",

  "idInjection": true,

  "properties": {},

  "validations": [],

  "relations": {

    "question": {

      "type": "hasOne",

      "model": "Question",

      "foreignKey": "questionId"

    }

  },
  "acls": [],

  "methods": []

}

// Question Model

{

  "name": "Question",

  "plural": "questions",

  "base": "PersistedModel",

  "idInjection": true,

  "properties": {

    "text": {

      "type": "string",

      "required": true

    },

    "type": {

      "type": "string",

      "required": true

    }

  },

  "validations": [],

  "relations": {},

  "acls": [],

  "methods": []

}

Here's my current solution for setting this up in Angular:

Survey.questions.create({ id: vm.survey.id }, {}).$promise.then(function(surveyQuestion) {

    console.log('survey question created!', surveyQuestion);

    SurveyQuestion.question.create({ id: surveyQuestion.id }, {
        text: 'What is your name?',
        type: 'text input'
    }).$promise.then(function(question) {

        console.log('question created!', question);

    });

});

The above does in fact create a SurveyQuestion instance and a Question instance, but both come back with a 'questionId' property which is actually the ID of the SurveyQuestion and not the Question.

Hope that wasn't too confusing, any ideas? Or better ideas for handling the Angular side?

[Spencer Strombotne]

You're going to want to use a belongsTo relationship (SurveyQuestion belongsTo Question). By defining a belongsTo relationship, you're asserting that a SurveyQuestion cannot possibly exist without a Question. Doing this will put the questionId foreign key in your SurveyQuestion schema. 

A consequence of this is that you'll have to create the Question object prior to creating the SurveyQuestion object that belongs to it.

Question.create({...}).$promise.then(function(question){
    SurveyQuestion.create({
        questionId: question.id
    }).$promise.then(function(surveyQuestion){

        surveyQuestion.question().$promise.then(...) //Get question for survey question

    });
});

Since you could have many SurveyQuestions that belongTo a Question, it's convenient to set up a hasMany relationship as well:

{

    "name": "Question",

    "plural": "questions",

    "base": "PersistedModel",

    "idInjection": true,

    "properties": {

        "text": {

            "type": "string",

            "required": true

        },

        "type": {

            "type": "string",

            "required": true

        }

    },

    "validations": [],

    "relations": {

        "surveyQuestions": {

            "type": "hasMany",

            "model": "SurveyQuestion",

            "foreignKey": "questionId" //Important to have same fk as the associated belongsTo relation

        }

    },

    "acls": [],

    "methods": []

}

Then you can create a new SurveyQuestion if you have access to an instance of a Question:

Question.create({...}).$promise.then(function(question){
    question.surveyQuestions.create({...}).$promise.then(......);

});