javascript - RethinkDB 用时间索引两个字段

Question

我有带有数据/表的 RethinkDB 让我们说带有大量数据行的“新闻”:

[
  {
    "author": "author1",
    "category_id": "business",
    "country": "id",
    "created_at": "Wed Aug 15 2018 09:26:52 GMT+07:00",
    "description": "description",
    "id": "74c25662-7f94-47ef-8a7e-5091924819a9"
  },

  {
    "author": "author2",
    "category_id": "business",
    "country": "id",
    "created_at": "Wed Aug 15 2018 09:26:52 GMT+07:00",
    "description": "description2",
    "id": "74c25662-7f94-47ef-8a7e-5091924819a9"
  },

  {
    "author": "author3",
    "category_id": "sport",
    "country": "id",
    "created_at": "Wed Aug 15 2018 09:26:52 GMT+07:00",
    "description": "description3",
    "id": "74c25662-7f94-47ef-8a7e-5091924819a9"
  },

  {
    "author": "author3",
    "category_id": "business",
    "country": "id",
    "created_at": "Wed Aug 15 2018 09:26:52 GMT+07:00",
    "description": "description4",
    "id": "74c25662-7f94-47ef-8a7e-5091924819a9"
  }
  .....
]

我需要为 category_id 和 created_at (timestamp) 创建索引并查询特定类别并按现在(特定日期)过滤仅有的。我想优化和加速查询结果

我可以在 javascript 中通过这样的过滤器为 category_id business 和 day 15 做到这一点:

r.table("news").filter({category_id: 'business'}).filter(
    r.row("created_at").day().eq(15)
)

但是我如何为 category_id 和 created_at 创建索引并在 created_at 的某一天查询它。

r.table("news").indexCreate( ???

谢谢

Answer 1

应该是这样的:

r.table('news').indexCreate('businessAndDate', function (doc) {
  return doc('category_id').add(doc('created_at').day().coerceTo('string'));
});

然后你可以:

r.table('news').getAll('business15', {index: 'businessAndDate'})

您可能希望在数据之间插入一个分隔符(如 'business-15')，并且不仅仅使用日期(否则，为什么要使用完整的时间戳？)，就这样了给你以及你愿意写多少 .add。 ;)根据the reference ，这称为任意索引。