我工作蒙戈和我想要做以下的事情： when a set of (lat, lon, uid) comes in:
1. the collection has lat as unique index, also for each lat the lon index is unique
2. if (lat, lon) pair exists in this collection, update
我正在使用Node（0.10.5）/ Mongo（2.4）/ Mongoose（3.6）來構建遊戲，並且我有一個像這樣的Mongoose模式。 。 var GameStateSchema = new Schema(
{
buildings: {
// This object will contain buildings of the same structure,
是否有可能爲在的ObjectId modelB引用一個子文件 ？ var C = new Schema({...});
var B = new Schema({c: [C]});
var A = new Schema({c: { type: ObjectId, ref: 'ModelB.ModelC' });
var Model_A = mongoose.model('ModelA', A
返回全體子文檔Arrary我需要讓所有的子文檔陣列從課程班，其中User.UserId =什麼和Courses.Status =活躍 Public Class User
Public Property UserId As String 'this is unique so i would like to index this, unless you think otherwise