如何在beforeSave和afterSave触发器中使parse.com中的两个查询原子化

Question

我在解析User（默认）和UserData时做了两个类。 BeforeSave触发器如下：

Parse.Cloud.beforeSave(Parse.User, function(request, response) {
var userDataObject = new Parse.Object("UserData");
var fromUserPointer = {"__type":"Pointer","className":"_User","objectId":request.object.id}; 

return userDataObject.save({score: 0, ideasCount: 0, followersCount:0, return:0}).then(function (userData) {
    var userDataPointer = {"__type":"Pointer","className":"UserData","objectId":userData.id};
    request.object.set("userData", userDataPointer);
    response.success();
}, function(error) {
    response.error(error.message);
});

}）;

它保存用户的UserData并获取其UserData指针字段并保存在UserData类中。

Parse.Cloud.afterSave(Parse.User, function(request) {   
Parse.Cloud.useMasterKey();
var userPointer = {"__type":"Pointer","className":"_User","objectId":request.object.id};
var userData = request.object.get("userData");
if (userData) {
    var userDataPointer = {"__type":"Pointer","className":"UserData","objectId":userData.id};
    var userDataQuery = new Parse.Query("UserData");
    userData.set("user", userPointer);
    return userData.save().then (function (userData) {
        var activityObject = new Parse.Object("Activity");
        return activityObject.save({fromUserData: userDataPointer, from:userPointer, 
            toUserData:userDataPointer, to:userPointer, type:"follow"});
    }).then (function (success) {

    }, function (error) {
        console.error("Error in afterSave(user) : " + request.object.id + ":" + error.message);
    });     
}

}）;

问题在于，在保存到User类之前，它有时不创建应创建的UserData。 因此，这两个触发器必须原子运行，而不必。