有没有更好的“加入"方式?数据使用地平线? [英] Is there a better way to "join" data using Horizon?

问题描述

我的数据在 RethinkDb 中看起来像这样:

My data looks something like this in RethinkDb:

[appointments]
{
    id: 1,
    date: "2016-01-01",
    stylistId: 1,
}

[stylists]
{
    id: 1,
    name: "Sue",
}

在客户端上，我想获取一个约会并将造型师嵌入到约会对象中，如下所示:

On the client, I want to fetch an appointment and have the stylist embedded in the appointment object like so:

{
    id: 1,
    date: "2016-01-01",
    stylist: {
        id: 1,
        name: "Sue",
    }
}

我可以使用此查询完成一些接近的事情:

I can achieve something close using this query:

return this.hz('appointments')
  .find(appointmentId)
  .fetch()
  .toPromise()
  .then(appointment => {
    return this.hz('stylists').find(appointment.stylistId)
      .fetch()
      .toPromise()
      .then(stylist => {
        appointment.stylist = stylist;
        return appointment;
      });
  })
  .then(appointment => this.appointment = appointment);

我想知道是否有更简洁的方法来实现预期的结果.我知道 RethinkDb 支持 Joins，但它看起来不像它在 Horizo​​n 中公开.我对 RxJS 也不太擅长，所以我想知道是否可以在那里更干净地完成连接.

I'm wondering if there is a cleaner way to achieve the desired result. I know that RethinkDb has support for Joins but it does not look like it's exposed in Horizon. I also am not very good with RxJS so I'm wondering if the join can be more cleanly done there.

推荐答案

尝试mergeMap和map组合

const appointmentFind$ = (appointmentId) => hz('appointments').find(appointmentId).fetch();
const stylistFind$ = (stylistId) => hz('stylists').find(stylistId).fetch();

appointmentFind$(appointmentId)
  .mergeMap((appointment) => stylistFind$(appointment.stylistId)
    .map((stylist) => ({ ...appointment, stylist })))
  .subscribe((x) => console.log(x));

我把它写在这里，所以它未经测试，但它应该像这样工作

I wrote it down here, so it's untested, but it should work somehow like this

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