Find Child's of Child document in Mongoose Node JS

-
This Article is basically to populate records/data/documents of child table and also for populate records/data/documents from Child's of child table in mongoose(Mongo DB).

 Suppose, you have three tables
1) Subjects
2) Chapters
3) Questions

 Questions schema is having the reference of Chapters (_id) and Chapters is having reference of Subjects (_id). So this is the Many to One relationship between them. 


If developer wants to populate Chapter name and Subject name with the Questions. Then you have to write find query like below:

Questions.find({})
  .populate({ 
     path: 'Chapters',
     populate: {
       path: 'Subjects',
       model: 'Subjects'
     } 
  })


Thanks for reading this article. Please share your comments on this article.

Comments

  1. Amy WongFebruary 4, 2019 at 4:15 AM

    Today I was riding in a bus and heard how the boys talked about this site secure online casino sites Speak as if it’s cool for a couple of hours so much money decided to take a risk and really thank you guys

    ReplyDelete

Post a Comment

Recent Post

Recent Posts Widget

Popular posts from this blog

Capture image from webcam java code, examples

-
import java.applet.Applet; import java.awt.BorderLayout; import java.awt.Component; import java.awt.Dimension; import java.awt.Frame; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Panel; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.awt.image.BufferedImage; import java.io.FileOutputStream; import java.net.MalformedURLException; import java.net.URL; import javax.media.Buffer; import javax.media.CaptureDeviceInfo; import javax.media.CaptureDeviceManager; import javax.media.Manager; import javax.media.MediaLocator; import javax.media.Player; import javax.media.control.FrameGrabbingControl; import javax.media.format.VideoFormat; import javax.media.util.BufferToImage; import javax.swing.JButton; import javax.swing.JComponent; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGE
Read more

Use of req.query, req.params and req.body in NODE JS

-
Image
I am writing this article for beginners. Because, at the time of learning node js, this is very confusing where and how we need to use req.query, req.params and req.body . I am going to explain these three req method below. 1.        Req.query 2.        Req.params 3.        Req.body Req.query: When request is coming in key and value pair, for example, if your URL looks like below URL http://localhost:3000/search?name=xyz&age=16 In the above URL, you can see that request is coming in key and value pair . First key is name and value is xyz, second key is age and value is 16. In the node js programing, if you want to parse this url then use req.query. Below is the code snippet to parse this URL. router.get('/search', function(req, res, next) {   var name = req.query.name;   console.log(`Name :  ${name}`)   var age = req.query.age;   console.log(`Age :  ${age}`)   res.send('Request has parsed see console');   }); Req.param
Read more

How to capture finger prints in java

-
Java code for capture finger prints. NBioBSPJNI.FIR_HANDLE hSavedFIR; hSavedFIR = bsp.new FIR_HANDLE(); bsp.Enroll(hSavedFIR, null); // Enroll bsp.Capture(hSavedFIR); // Capture // Get Text FIR if (bsp.IsErrorOccured() == false) { NBioBSPJNI.FIR_TEXTENCODE textSavedFIR; textSavedFIR = bsp.new FIR_TEXTENCODE(); bsp.GetTextFIRFromHandle(hSavedFIR, textSavedFIR); } // Get Binary FIR if (bsp.IsErrorOccured() == false) { NBioBSPJNI.FIR fullSavedFIR; fullSavedFIR = bsp.new FIR(); bsp.GetFIRFromHandle(hSavedFIR, fullSavedFIR); } You can capture both type in your database and file. 1)textFIR 2)BinaryFIR
Read more