mongoose - MongoDB Query Based on ObjectId Reference Condition -

-

मेरे पास MongoDB संग्रह बिल्लियों है जिसके पास एक ObjectId संदर्भ फ़ील्ड है zooId संग्रह चिड़ियाघर ।

मैं कैसे की तरह कुछ पूछताछ के बारे में जाना होगा

db.Cats.find ({zooId.zooName: 'San डिएगो '}) गिनती ()

जहां क्वेरी की स्थिति zooName में zooId संदर्भ में है? < / P>

मैं मोंगोज का उपयोग करके समझता हूं, मैं कुछ संदर्भों को वास्तव में लाने के लिए populate विधि को कॉल कर सकता हूं, लेकिन मैं मोंगॉड कंसोल या रोबोमोंगो में सीधे कैसे इसी तरह की बातें करूँगा?

धन्यवाद!

"post-text" itemprop = "text">

सरल कोडिंग: 

  var cats = 0; Db.Zoo.find ({zooName: 'San Diego'}) .पूर्व (फ़ंक्शन (zooItem) {var id = zooItem._id; cats + = db.Cat.find ({'zooId': id})। गणना ( );}); प्रिंट (बिल्लियों);

Comments

Post a Comment

Popular posts from this blog

c# - XML serialize base class without knowing derived class -

-
I know that a XmlSerializer throws an exception if the type passed does not match the type Since then the serializer was created My question is: Is it possible to serial the base type without knowing the derivative type? Consider the following scenario: The following classes are in a top-level domain and there is no dependency : Public Class Serializer {Private Static String Serialize (base basedata) {var serializer = New XML serializer (typefile); Var sb = new stringbilder (); (Var author = XmlWriter.Create (sb)) using {serializer.Serialize (author, bassadata); } Return sb.ToString (); } Private static string Deserialize (...) {...}} Public class base {public string name {get; Set; }} The following derivative classes have additional dependencies on things like UI components, structure, etc. (and more on this later): [Export (Typ (IMyComponent)] Public category was created: Base, IMyComponent, INotifyPropertyChanged {public new string name {get {return base.Name; ...
Read more

c# - UnhandledExceptionMode.ThrowException for AppDomain.UnhandledException -

-
I want to set unhandledExceptionMode.ThrowException for current AppDomain and not only for application threads. An exception from the second thread should also be handled by my current Donan_Unimated exception handler. Is it possible? Here's my code: Fixed class program {/// & lt; Summary & gt; Main entry point for the application /// & lt; / Summary & gt; [STAThread] static zero major () {applications Set unhandled exception mode (unwanted exception. Throws up); AppDomain.CurrentDomain.UnhandledException + = New UnrestrictedExceptionEndception (CurrentDomain_UnhandledException); Application.EnableVisualStyles (); Application.SetCompatibleTextRenderingDefault (wrong); Application.Run (New Form 1 ()); } Static Zero CurrentDomain_UnhandledException (Object Sender, UnhandledExceptionEventArgs E) {File.AppendAllText ("Log.txt", (Exception) e.ExceptionObject). Message + environment. Newline); }} Maybe you search for the behavior provided by Applic...
Read more

udp - The relationship between MTU and size of skb in xmit function -

-
I encounter a problem when I develop a network card driver in Linux. As we all know that the MTU fragment refers to the maximum size of the IP packet. And the squad will be sent to the exclamation function, which will include 14bytes including DST MAC Adrer, SRC MACEdre and LNG. But it is very strange that when I use different values ​​for MTU, the pair size is different, sometimes it is 10bytes, sometimes it is 14bytes, it is based on the size of the MTU For example, I use 7828 as the size of the UDP payload, when MTU is 7700, the size of the scab in the XMT function is 7714, while when MTU is 7800, the size of the scalable is 7810. Can anyone explain this? I think there are some aligned boundaries for the IP packet, but I did not find it. I searched the answers from the Internet, and I found that there is a line limit for the payload field. The frame payload field must be aligned to 8 bytes. So if MTU is 7700, then the correct size of the IP frame should be 7680 + 20 = 7700 ...
Read more