RethinkDB 上具有 OR 条件的两个过滤器

Question

我有一个结构：

type Talk struct {
    Id string `gorethink:"id,omitempty"`
    MatchId string
    UserIdX string
    UserIdY string
    UserNameX string
    UserNameY string
    CreatedAt time.Time
}

我当前的 Talk 结构如下所示：

{
    "CreatedAt": Wed Sep 14 2016 21:36:26 GMT+02:00 ,
    "MatchId":  "172d51fa-438b-49a5-bbe5-422377f09336" ,
    "UserIdX":  "acc4e0b6-d33b-4755-9c0a-ae5309c2ba75" ,
    "UserIdY":  "03f76d8b-ed6a-4c0f-9cde-27b17c9e7cdb" ,
    "UserNameX":  "Barbara" ,
    "UserNameY":  "Louis" ,
    "id":  "ead3f1b0-b242-4c6d-8027-a59572b58649"
}

如何通过单个查询检索谈话内容，其中：

(UserIdX == talk.UserIdX AND UserIdY == talk.UserIdY) OR (UserIdX == talk.UserIdY AND UserIdY == talk.UserIdX)

我实际上是这样做的：

func (talk *Talk) GetTalkByUsersId() bool {
    talk1 := new(Talk)
    talk2 := new(Talk)

    curs, _ :=  r.Table("Talks").
                Filter(r.Row.Field("UserIdX").Eq(talk.UserIdX)).
                Filter(r.Row.Field("UserIdY").Eq(talk.UserIdY)).
                Run(api.Sess)

    curs2, _ :=  r.Table("Talks").
                Filter(r.Row.Field("UserIdX").Eq(talk.UserIdY)).
                Filter(r.Row.Field("UserIdY").Eq(talk.UserIdX)).
                Run(api.Sess)

    curs.One(&talk1)
    curs2.One(&talk2)
    if talk1.Id == "" && talk2.Id == "" {
        return false
    }
    if talk1.Id != "" {
        talk.copyTalk(talk1)
    } else {
        talk.copyTalk(talk2)
    }
    return true
}

我怎样才能使它以更简单的方式工作？

Answer 1

我将在这里召集@daniel-cannon，但我认为这就是您正在寻找的，并且会极大地简化此查询并将其减少为单个查询。但只有两个提示：

r.And 和 r.Or 以及它们的两个用例非常适合您做一些棘手的逻辑条件。
- https://www.rethinkdb.com/api/javascript/#and
- https://www.rethinkdb.com/api/javascript/#or
您可以向 .Filter 提供匿名函数来执行一些使用简化的 r.Row 模式会有些丑陋的事情。

r.Table("talks").Filter(func(talk r.Term) r.Term {
    return r.Or(
        r.And(talk.Field("UserIdX").Eq(UserIdX), talk.Field("UserIdX").Eq(UserIdY)),
        r.And(talk.Field("UserIdY").Eq(UserIdX), talk.Field("UserIdX").Eq(UserIdY)),
    )
}).Run(api.Sess)

希望对您有所帮助！

RethinkDB 上具有 OR 条件的两个过滤器

Two filters with an OR-condition on RethinkDB

go

rethinkdb