CODEWITHSUNDEEP
mongodbloopbackjs
Sam Munroe
Sam Munroe

Reputation: 1418

Loopback relations not populating array of Object IDs

I have 2 models so far: workflow-core,workflow-step'

Workflow core has a steps property that is of type array and contains 1-many steps. When calling get on workflow-core the response body is not populating the steps array with the actual step objects.

workflow-core.json:

{
"name": "workflow-core",
"base": "PersistedModel",
"idInjection": true,
"options": {
  "validateUpsert": true
},
"injectOptionsFromRemoteContext": true,
"properties": {
  "name": {
    "type": "string",
    "required": true,
    "default": "Untitled"
  },
  "user_id": {
    "type": "string",
    "required": false
  },
  "steps": {
    "type": "array",
    "required": false,
    "default": []
  }
},
"validations": [],
"relations": {
  "steps": {
    "model": "workflow-step",
    "type": "embedsMany"
  }
},
"acls": [
  {
    "accessType": "*",
    "principalType": "ROLE",
    "principalId": "$unauthenticated",
    "permission": "DENY"
  }
],
"methods": {}
}

workflow-step.json:

{
"name": "workflow-step",
"base": "PersistedModel",
"idInjection": true,
"options": {
  "validateUpsert": true
},
"properties": {
  "name": {
    "type": "string",
    "required": true,
    "default": "Untitled Step"
  },
  "status": {
    "type": "string",
    "default": "waiting"
  }
},
"validations": [],
"relations": {},
"acls": [],
"methods": {}
}

What the Loopback Explorer says I should get (and what I want):

{
  "name": "Untitled",
  "user_id": "string",
  "steps": [],
  "id": "string",
  "workflow-steps": [
    {
      "name": "Untitled Step",
      "status": "waiting",
      "id": "string"
    }
  ]
}

What I am getting:

{
    "name": "Updated with step",
    "user_id": "231569461654",
    "id": "5b75bc769b3143103cb787c2",
    "workflow-steps": [],
    "steps": [
      "5b760fff24ccc23934fef240"
    ]
  }

hasMany seems to do the same thing except there is no workflow-steps array property in the response body

Upvotes: 2

Views: 738

Answers (2)

Deepesh Kumar
Deepesh Kumar

Reputation: 114

What worked for me is given below. If there is an array of IDs in a property, make use of referencesMany relation type.

Model A :

{
    id: 100,
    bIdList: [200, 201]
}

Model B :

{
    id: 200,
    active: true
},
{
    id: 201,
    active: false
}

Remember bIdList should be array of ObjectIDs, not strings.

In Model A add relation to Model B as follows :

"relations": {
    "bRelation": {
        "type": "referencesMany",
        "model": "B",
        "foreignKey": "bIdList"
     }
},

For a find query like the one below,

modelA.findOne({include: 'bRelation'});

It will return a result like this,

{
    id: 100,
    bIdList: [200, 201]
    bRelation: [
        {
            id: 200,
            active: true
        },
        {
            id: 201,
            active: false            }
    ]
}

Link to the Loopback 3 doc detailing the same. https://loopback.io/doc/en/lb3/Embedded-models-and-relations.html#referencesmany

Upvotes: 0

Sam Munroe
Sam Munroe

Reputation: 1418

This ended up being an easy fix:

  1. I changed the step relation in workflow-core.json:

    "relations": {
    "steps": {
       "type": "hasMany",  <-- used hasMany instead of embedsMany
       "model": "WorkflowStep",
       "foreignKey": ""
     }
},

  2. When using the api explorer window, I needed to add the filter: {"include": "steps"}

enter image description here

Not sure if this was part of it but I changed my model names as follows:

workflow-core ---> WorkflowCore
workflow-step ---> WorkflowStep

Upvotes: 1

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