title: I want to know about mongodb
body: <p>I'm currently creating an API server that reads and writes. Using MongoDB</p>
  
  <p>The library uses Mongoose.</p>
  
  <p>I wonder if <code>db.close()</code> must be used when reading and writing.</p>
  
  <p>datamodel.js:</p>
  
  <pre><code>var db = mongoose.connect('mongodb://localhost/testdb', {useNewUrlParser: true,useUnifiedTopology:true});
  mongoose.Promise = global.Promise;
  
  .....
  Boards = mongoose.model("boards", BoardSchema);
  exports.Boards = Boards;
  </code></pre>
  
  <p>routes/getList.js:</p>
  
  <pre><code>let result = await Boards.find().sort({"date": -1});
  </code></pre>
  
  <p>Should I close the DB declared above with <code>db.close()</code> when reading or writing?</p>