Question

我使用Parse平台作为后端，我有帖子和媒体类。每个（img，file，....）在 Media 类中的Parse对象中，每个都有一个列，指向Posts类中的Post对象。

我正在尝试使用每个帖子的媒体获取所有帖子，我如何通过一个查询来完成？

var Posts = Parse.Object.extend("posts");
    var query = new Parse.Query(Posts);
    var newObject = [];
    query.find().then(function(data){

        for (var i = 0; i < data.length; i++) {
            var item = data[i].toJSON();
            var newData = {};
            newData.objectId = item.objectId;
            newData.user = {
                userId: item.user.objectId,
                fullName: item.user.fullName,
                picture: item.user.imageUrl,
                userName: item.user.userName,
            };
            newData.date = item.createdAt;
            newData.hasImages = item.hasImages;
            newData.postBody = item.postBody;
            if(item.hasImages){
                var Media = Parse.Object.extend("media");
                var mediaQuery = new Parse.Query(Media);
                mediaQuery.limit(10);
                mediaQuery.descending("createdAt");
                mediaQuery.matches("post", item.objectId);
                mediaQuery.find().then(function(data){
                    newData.images = data;
                });
            }
            newObject.push(newData);
        }
        console.log(newObject);
    });

Answer 1

最佳方法是在媒体发布之间建立一对多关系，以便每个发布包含多个媒体对象，然后您可以使用以下代码：为了获得包含所有媒体的所有帖子..

＆＃13;

var Posts = Parse.Object.extend("posts");
var query = new Parse.Query(Posts);

// add some coditions to the Posts query here if needed

query.include("media");  // include the media relation (0..n) 

// if you want to fetch only posts that have media under it you can use the following line of code
query.exists("media"); // make sure that only posts with media will be populated

query.find().then(function(posts){
  
  // here you have the list of posts
  // in order to access property of a post you can use the following code:
  
  for (var i=0;i < posts.length;i++){
    var post = posts[i];
    var postMedia = post.get("media"); // get all media objects in a specific post
    //..
  }
  
},function(error){
  // error 
});

＆＃13;

您可以在here

中阅读有关Parse关系的更多信息

来自不同班级

1 个答案: