查询复杂键中的ANY值(又称通配符) [英] Query for ANY value in complex key (AKA wildcard)

问题描述

我经历了文档和SO问题，但没有找到针对我的特殊情况的明确答案.

I went through docs and SO questions but didn't find any clear answer for my particular case.

具有这种复杂的(发射数组)键映射功能

Having this complex (emitting array) key map func in view

function(doc) {
    if (doc.userFirstName && doc.userLastName && doc.userGender && doc.homeCountry && doc.homeCity) {
      emit([
        doc.userFirstName,
        doc.userMiddleName,
        doc.userLastName,            
      ], null)
    }

我想用一些值为空的查询它-因此查询可以接受键中的 ANY 值，即

I want to query it with values some of which are empty - so query could accept ANY values from the key, i.e.

userFirstName = *anyvalue*
userMiddleName = *anyvalue*
userLastName = "Mozart"

如果可能的话-我的startKey =和endKey =请求参数应该是什么样?我尝试过

If it's possible - what should my startKey= and endKey= request parameters look like? I tried

startkey=[{},{},"Mozart"]&endkey=[{},{},"Mozart"]

但无济于事-没有行..

but with no avail - got no rows..

推荐答案

在沙发数据库查询中，"Any_value"通配符是不可能的(但是，对开发人员的问题-为什么不呢?)，因此执行多维度查找的唯一方法空(= accept_any)值用于维护非空搜索值的所有可能组合的索引.我最终得到了这个_design文档:

"Any_value" wildcard in couchdb query isn't possible (yet, question to devs - why not?), so the only way to perform multy-dimensional lookup with empty (=accept_any) values is to maintain indexes for all possible combinations of non-empty search values. I ended up with this _design doc:

let ddoc = {
      '_id': '_design/search',
      'views': {
        'firstOnly': {'map': firstOnly},
        'middleOnly': {'map': middleOnly},
        'lastOnly': {'map': lastOnly},
        'firstLast': {'map': firstLast},
        'firstMiddle': {'map': firstMiddle},
        'middleLast': {'map': middleLast}
      }
    };

其中(即已知的MiddleName和lastName)映射函数如下所示:

where (i.e. for known middleName and lastName) map function looks like:

const middleLast =
  `function(doc) {
    if (doc.userMiddleName && doc.userLastName) {
      emit([
        doc.userMiddleName,
        doc.userLastName,
      ], null)
    }
  }`;

然后我可以根据已知的数据集查询相应的视图.

Then can I query corresponding view depending on dataset known.

因此，六个复杂的键索引而不是一个.非常繁重(如果有上百万条记录，则很遗憾)，但这是唯一可能的解决方案.

So six complex key indexes instead of one. Quite heavy (in case of millions of records), but, unfortunately, the only possible solution.

感谢所有响应者，您的帮助无价.

Thanks to all responders, your help is unvaluable.

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