title: What is the best practice for joins in MongoDB?
body: <p>I have two class called <code>School</code> and <code>Student</code> as you see. I want to search for "students that school names are bla bla bla" and "schools that have students which has higher grade than 90". I read some documents but I am a little confused.</p>
  
  <pre><code>public class School extends BasicDBObject  {
    private int id;
    private String name;
    private String number;
    private List&lt;Student&gt; studentList = new ArrayList&lt;Student&gt;();,
  
    //getter and setters
  }
  
  public class Student extends BasicDBObject{
    private int id;
    private String name;
    private String grade;
    private School school;
  
    //getter and setters
  }
  </code></pre>