使用nodejs在貓鼬模式中添加數值

Question

我正在開發在線課程應用程序。我創建了一個課程註冊集合，用於存儲課程名稱和註冊該課程的用戶。 Mongoose模式看起來像這樣。它的名字是courseEnrollment.js。

var mongoose = require('mongoose'); 
var Schema = mongoose.Schema; 

var courseEnrollment = new Schema({ 


courseEnrolled: [{courseName : String}, 
       {username : [{user : String}]} 
       ] 

}, {collection : 'courseEnrollment'}); 

module.exports = mongoose.model('courseEnrollment', courseEnrollment); 

當用戶點擊註冊時，GET請求將轉到'localhost：3000/learn /：courseName/enroll'。 在該路由處理程序中，我將用戶課程註冊信息存儲在兩個不同的集合中。 1）在課程註冊收集，我上面顯示。 2）在用戶帳戶信息中，用戶名，密碼等存儲在那裏，我也在存儲用戶註冊的課程。

現在我現在面臨的問題是，它只會更新User集合，而不是因爲某種原因導致的courseEnrollment集合。它會給出以下錯誤。

events.js:141 
    throw er; // Unhandled 'error' event 
^

TypeError: Cannot read property 'push' of undefined 
at /home/mobileedx/WebstormProjects/passportAuthentication/routes/index.js:387:47 
at Query.<anonymous> (/home/mobileedx/WebstormProjects/passportAuthentication/node_modules/mongoose/lib/model.js:3340:16) 
at /home/mobileedx/WebstormProjects/passportAuthentication/node_modules/mongoose/node_modules/kareem/index.js:259:21 
at /home/mobileedx/WebstormProjects/passportAuthentication/node_modules/mongoose/node_modules/kareem/index.js:127:16 
at nextTickCallbackWith0Args (node.js:420:9) 
at process._tickCallback (node.js:349:13) 

這裏是我的路由處理程序內代碼的 'localhost：3000 /學習/：courseName /註冊'

/** 
    * Here If a user clicks on enroll, then the GET request will come on this page. If user is not authenticated then it 
* will redirect to the login page. If user is logged in then, user will get the courseHome page. 
*/ 

router.get('/learn/:courseName/enroll', isAuthenticated, function (req, res) { 

    var user = req.user.username; 
    var course = req.params.courseName; 

    console.log('user trying to enroll is: ' + user); 
    console.log('coursename user is trying to enroll is: ' + course); 

    courseEnrollment.findOne({ 'courseEnrolled.courseName' : req.params.courseName }, function(err, courseEnroll) { 
     // In case of any error, return using the done method 
     if (err) { 
      console.log('Error in SignUp: ' + err); 
      return done(err); 
     } 
     console.log('courseEnroll value is: ' + courseEnroll); 

     courseEnroll.courseEnrolled.username.push({ "user": req.user.username}); 

     courseEnroll.save(function (err, data) { 
      if (err) 
       throw err; 
      else { 
       console.log('course Updated in courseEnrollment collection'); 
      } 
     }); 
    }); 


    // When a user clicks on 'enroll' to enroll to a course, then the course name should be added in the 
    // user's courseEnrolled list as well. This is what we are doing here. 


    User.findOne({ 'username' : req.user.username }, function(err, user) { 
     // In case of any error, return using the done method 
     if (err) { 
      console.log('Error in SignUp: ' + err); 
      return done(err); 
     } 
     console.log('user value is: ' + user); 
     console.log('username value is: ' + user.username); 
     user.courseEnrolled.push({ "courseName": course}); 

     user.save(function (err, data) { 
      if (err) 
       throw err; 
      else { 
       console.log('course Updated in user account collection'); 
      } 
     }); 

     res.render('home', {user: req.user}); 
    }); 
}); 

請讓我知道，我要去的地方錯在這裏。我可以使用貓鼬人口填充courseEnrollment集合中用戶集合的用戶名字段的用戶名。如果是，那麼該怎麼做。 謝謝。

Answer 1

從我能猜到的是模式有問題。您的課程註冊模式。它應該像下面一樣。每個課程包含一個對象的數組。其中包含有關其名稱和註冊用戶的信息。

courseEnrolled: [{ 
      courseName : String, 
      username : [{user : String}] 
    }] 

希望它有幫助。

.............................................. ...

好吧，如果這只是維護加入特定課程的用戶的模式。那麼你可以按照下面的模式

var courseEnrollment = new Schema({ 
    courseName : String:, 
    usersEnrolled : [String] 
}, {collection : 'courseEnrollment'}); 

它可以像這樣查詢訪問。

courseEnrollment.findOne({ 'courseName' : req.params.courseName }, function(err, courseEnroll) { 
    // In case of any error, return using the done method 
    if (err) { 
     console.log('Error in SignUp: ' + err); 
     return done(err); 
    } 
    console.log('courseEnroll value is: ' + courseEnroll); 

    courseEnroll.username.push({ "user": req.user.username}); 

    courseEnroll.save(function (err, data) { 
     if (err) 
      throw err; 
     else { 
      console.log('course Updated in courseEnrollment collection'); 
     } 
    }); 

}）;