解析Javascript云代码嵌套查询

Question

I am writing a script on parse.com's javascript cloud code SDK. I am having trouble with the "doesNotMatchQuery" method. I have a "class" called activity, this contains a field called movie and a field called fromUser containing the user object of that activity,

i have a class called movie. I want to get all movies that do not have activity from this user.

The code I am using(which i know is wrong and doesNotMatchQuery is not the correct method).

  Parse.Cloud.define("recommendations", function(request, response) {
  var user = request.user;

  var queryUserActivity = new Parse.Query("Activity");
  queryUserActivity.equalTo("fromUser",user);

  var query = new Parse.Query("Movie");
  query.doesNotMatchQuery("movie", queryUserActivity);
  query.find({
    success: function(results) {
      response.success(results);
    },
    error: function() {
      response.error("movie lookup failed");
    }
  });
}

The problem is in the doesNotMatchQuery, only matches against a field, whereas i want it to match against the result objects from the "query", method "doesNotMatchKeyInQuery" comes close but still doesn't offer the ability to match the results of the query with a key.

Answer 1

The code below finds the list of the movie objects that you do not want to return via Activity table and excludes them from you final Movie records.

var _ = require('underscore');
Parse.Cloud.define("recommendations", function(request, response) {

var user = request.user;
var queryUserActivity = new Parse.Query("Activity");
queryUserActivity.equalTo("fromUser",user);
queryUserActivity.select("movie");

queryUserActivity.find().then(function(activities) {

    var movieObjIds = _.map(activities, function(activity) {
        return activity.get("movie").id; 
    });
    var query = new Parse.Query("Movie");
    query.notContainedIn("objectId", movieObjIds);
    return query.find();

}).then( function(results) {
      response.success(results);
}, function(error) {
      response.error(error);
});
});