How to configure & use persistent data objects in SAP HANA Cloud?

I want to create a simple project management application in Java at the SAP HANA Cloud Platform. Users can add persons to projects and define the working hours of a person who works on a project.

I created successfully a small application logic. However it's not clear to me how I should define the persistent data objects. And how to store and read the data in the right way.

I created the classes "Project" and "Person" to add data (see below).

How can I create a relationship between them and store the hours of work a person spent on a project?

On an ERM, I know the solution: A 1:n relation between Person and Project and an extra table between them with "projectID","personID" and "workingHours".

So far the app writes data with the function "addNewPerson":

addNewPerson : function( sFirstName, sLastName, oTable ) {  
          var _this = this;  
          _this.odataServiceUrl = personsListOdataServiceUrl;  
          jQuery.ajax({  
             url : _this.odataServiceUrl + "/Person?$format=json",  
             type : 'POST',  
             contentType : 'application/json',  
             data : JSON.stringify({  
                                     firstName : sFirstName,  
                                     lastName : sLastName  
                                  }),  
             success : function(data) {  
               _this.getView().getModel().refresh();  
               oTable.unbindRows().bindRows("/Person");  
      },  
             error : function(jqXHR, textStatus, errorThrown) {  
           sap.ui.commons.MessageBox.alert("Failed to add person: " + textStatus+ "\n" + errorThrown);  
             }  
      }); },  

To read the data, I simply bind the rows to the object.

So, how can I create the data objects the right way? And how can I read and write the data to the objects?

Person.java:

package com.sap.netweaver.cloud.sample;
import javax.persistence.*;
@Entity
@Table(name = "T_PERSON")
@NamedQuery(name = "AllPersons", query = "select p from Person p")

public class Person {
    @Id
    @GeneratedValue
    private long id;
    @Basic
    private String firstName;
    @Basic
    private String lastName;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public void setFirstName(String param) {
        this.firstName = param;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setLastName(String param) {
        this.lastName = param;
    }

    public String getLastName() {
        return lastName;
    }
}

Project.java:

package com.sap.netweaver.cloud.sample;

import javax.persistence.Basic;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

@Entity
@Table(name = "T_PROJECT")
@NamedQuery(name = "AllProjects", query = "select p from Project p")
public class Project {

    @Id
    @GeneratedValue
    private long id;
    @Basic
    private String projectName;
    @Basic
    private String projectDesc;
    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public void setProjectName(String param) {
        this.projectName = param;
    }

    public String getProjectName() {
        return projectName;
    }

    public void setProjectDesc(String param) {
        this.projectDesc = param;
    }

    public String getProjectDesc() {
        return projectDesc;
    }
}