Node.js Can'；t使用nodejs+；数据库

我无法在azure中更新或获取此集合的信息 我确信连接字符串和每件事情都是正确的 我就是不能处理这些收集

Nodejs

var dbApp=dbs.db（'test'）中的问题

错误

---

连接的初始调用中是否有错误？使用哪个sdk？

 MongoClient.connect(url, {
            useUnifiedTopology: true
            },async function (err, dbs) {
             var dbApp=dbs.db('test'); //the problem in this line 
             dbApp.collection("users").findOne({ userName:Drawer},async function(r,info){
               if(r)throw r;
                  dbApp.collection("users").updateMany({ userName: Drawer },
                   { $set: { numOfDrawings: info.numOfDrawings+1 },
                     },)
                      await drawings.save();
                      await allDrawings.save();
                      res.json("Painting Added Successfuly !");
                      db.close;
                                                      });
                                                    });
                                                    
                                               
                                               }
                                               
                                          });        

(node:5637) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'collection' of undefined
at /home/ekko/nodejs/ch_Paintings/src/controller/authController.js:141:65
at /home/ekko/nodejs/ch_Paintings/node_modules/mongoose/lib/model.js:4843:16
at /home/ekko/nodejs/ch_Paintings/node_modules/mongoose/lib/model.js:4843:16
at /home/ekko/nodejs/ch_Paintings/node_modules/mongoose/lib/helpers/promiseOrCallback.js:24:16
at /home/ekko/nodejs/ch_Paintings/node_modules/mongoose/lib/model.js:4866:21
at /home/ekko/nodejs/ch_Paintings/node_modules/mongoose/lib/query.js:4410:11
at /home/ekko/nodejs/ch_Paintings/node_modules/kareem/index.js:135:16
at processTicksAndRejections (internal/process/task_queues.js:79:11)
at runNextTicks (internal/process/task_queues.js:66:3)
at processImmediate (internal/timers.js:429:9)