Javascript 如何在Bookshelf.js中创建与自定义字段名的多对多关系？

我想在Bookshelf.js中创建一个多对多关系，并自己指定FK列的名称。我还希望能够访问Bookshelf中的helper表，如下所示：

var Doctor = bookshelf.Model.extend({

  patients: function() {
    return this.belongsToMany(Patient).through(Appointment);
  }

});

var Appointment = bookshelf.Model.extend({

  patient: function() {
    return this.belongsTo(Patient);
  },

  doctor: function() {
    return this.belongsTo(Doctor);
  }

});

var Patient = bookshelf.Model.extend({

  doctors: function() {
    return this.belongsToMany(Doctor).through(Appointment);
  }

});

---

我该怎么做呢？

考虑到上面的例子，我们可以这样做：

var Doctor = bookshelf.Model.extend({

  tableName: "d_doctor",
  idAttribute: "d_doctorid",

  patients: function() {
    return this.belongsToMany(Patient).through(Appointment,"a_d_doctorid","a_p_patientid");
  }

});

var Appointment = bookshelf.Model.extend({

  tableName : "a_appointment",
  idAttribute : "a_appointmentid",

  patient: function() {
    return this.belongsTo(Patient,"a_p_patientid");
  },

  doctor: function() {
    return this.belongsTo(Doctor,"a_d_doctorid");
  }

});

var Patient = bookshelf.Model.extend({

  tableName : "p_patient",
  idAttribute : "p_patientid",

  doctors: function() {
    return this.belongsToMany(Doctor).through(Appointment,"a_p_patientid", "a_d_doctorid");
  }

});