有没有办法从结果中清除重复记录? [英] is there a way to clear duplication record from results?

问题描述

我有一个视图，但是确实从视图结果中复制了文档，如下所示，如何获得重复的结果并获得唯一的?预先谢谢你

I have a view but did have duplicated documents from the results of view as like following, how can I get the duplicate results and get the unique? thank you in advance

{
"total_rows": 9,
"offset": 0,
"rows": [

        {
            "id": "xxxx",
            "key": "12345",
            "value": {
            "_id": "abc123",
            "_rev": "4-8db4da81d1e20afcea0a328fb16e7ec8",
                "field1": "abc",
                "field2": "dfr"
            },

            {
                "id": "xxxx",
                "key": "12345",
                "value": {
                    "_id": "abc123",
                    "_rev": "4-8db4da81d1e20afcea0a328fb16e7ec8",
                    "field1": "abc",
                    "field2": "dfr"
                },
            ]
        }

视图是这样的

function(doc) {
if(doc){
    for (var i in doc.item){
            emit(doc.item[i].key,doc);
        }
    }  
}

视图由调用 ...._ view/duplicate?key ="12345"

view called by ...._view/duplicate?key="12345"

执行以下reduce时，我总是遇到此错误:" error":"reduce_overflow_error"，"reason":"Reduce输出必须缩小更多 迅速:

I always had this error when execute the following reduce :"error":"reduce_overflow_error","reason":"Reduce output must shrink more rapidly:

function (keys, values, rereduce) {
var uniqueKey = [];
var newValues = [];
for (var i=0; i<values.length; i++) {
    if (uniqueKey.indexOf(values[i]._id)==-1) {
        uniqueKey.push(values[i]._id);
        newValues.push(values[i]);
    }
}
return newValues;

}

推荐答案

问题是您的地图功能:

function(doc) {
if(doc){
    for (var i in doc.item){
            emit(doc.item[i].key,doc);
        }
    }  
}

这样做，您会多次发出相同的文档，因此，如果视图结果中有重复的文档，也就不足为奇了.如果要返回文档的所有项目而没有重复项，则可以执行以下操作:

By doing that, you emit the same document several times, therefore it shouldn't come as a surprise that you have duplicate documents in your view's results. If you want to return all the items for a document without any duplicate, you can do something as simple as that :

function(doc) {
  if(doc.item) {
    emit(doc.item, null)
  }     
} 

还请注意，我执行emit(doc.item, null)而不是emit(doc.item, doc).发出文档是一种不好的做法，您应该改为使用选项include_docs=true查询视图.否则，您的视图索引将具有与数据库相同的大小.

Also please note that I do emit(doc.item, null) and not emit(doc.item, doc). It is a bad practice to emit the document, you should instead query the view with option include_docs=true. Otherwise your view index will have the same size as your database.

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