Query based on Pointer Values

Question

I have read majority of the questions which quite havent helped me.

So I have three tables, User (parse Default), DataSet and Datapoint.

DataSet is linked to User based on Pointer.

Datapoint is linked to Dataset based on Pointer (object ID of DataSet).

I can easily load DataSets for each User Parse. What i would like to do is load datapoints for a dataset.

I am using Angular, and I can pass the dataset object to, and based of that ID I want to be able to get datapoints for that dataset.

He is what I have so far.

getmyDataPoint: function getMyDataPoint(dataset, callback) {

      //get object ID of dataset
      var datasetid = dataset.id;


      var query = new Parse.Query(Datapoint);
      query.include('inDataset');

     //inDataset is column name that is pointer, linking to dataset. 

      query.EqualTo('inDataset', datasetid);
      query.find({
          success: function(results) {
              callback(results);
              alert("found some here " + results);
          },
          error: function(error) {
              alert("Error: no datapoint found " + error.message);
          }
      });

As you would know this quite doesnt work. Any help?

You say you are using pointers, then you say you are using the ID directly. You would unlock more power of Parse if you use actual pointers. — Timothy Walters
– Timothy Walters, Commented Jan 12, 2015 at 5:45
In that case you should compare to the dataset object instead of its ID, as per my answer. — Timothy Walters
– Timothy Walters, Commented Jan 12, 2015 at 5:52

Timothy Walters · Accepted Answer · 2015-01-12 05:51:16Z

2

Lets assume you fix up your classes as follows:

DataSet class
  user: Pointer<User>
Datapoint class
  inDataset: Pointer<DataSet>

Now you can query for Datapoint rows where the inDataset column matches a DataSet quite easily:

query.equalTo('inDataset', dataset);

Under the covers Parse's SDK extracts the object ID and matches on that, but using an actual pointer makes other types of queries possible that you couldn't do with just the strings as you are currently doing it.

answered Jan 12, 2015 at 5:51

Timothy Walters

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1 Comment

smushi Over a year ago

oh, I feel so dumb. It was so simple.was almost there as well. Thanks!

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