更新嵌套文档并在mongodb中增加 [英] Update a nested document filed and increment in mongodb

问题描述

我想更新嵌套文档，如果存在，则使用新值增加旧值或插入新文档。

I want to update a nested document filed if present increment an old value with new value or insert a new document.

New Zealand,Waikato,Hamilton,1004
New Zealand,Waikato,Auckland,145
New Zealand,Otago,Dunedin,1068

Json

Json

{ "_id" : ObjectId("55e7d2a72f68907c17cfcb2f"), "country" : "New Zealand", 
"regions" : [ { "region" : "Waikato", "size" : 1004 }, 
{ "region" : "Waikato", "size" : 145 }, { "region" : "Otago", "size" : 1068 } ] }

在文档 regions 数组中本质上是动态的。在上面的文档中，我需要更新~Waikato`的增量字段 size 的值。而不是在区域数组中放入另一条记录。

In document regions array is dynamic in nature. In above document I need to update an increment field size value of ~Waikato`. Instead of putting an another record in array of regions.

BasicDBObject query = new BasicDBObject();
query.put("country", "New Zealand");
query.put("regions.$.region", "Waikato");
BasicDBObject data = new BasicDBObject().append("$inc", new BasicDBObject().append("regions.$.size", 145));
BasicDBObject command = new BasicDBObject();
command.put("$set", data);
collection.update(query, command, true, false);

我需要这样的输出：

I need output like these:

{ "_id" : ObjectId("55e7d2a72f68907c17cfcb2f"), "country" : "New Zealand", "regions" : [ { "region" : "Waikato", "size" : 1149 }, { "region" : "Otago", "size" : 1068 } ] }

请建议我在这些问题上。

Please suggest me on these issue.

推荐答案

你的位置 $ 运算符只属于更新部分而不是查询。还需要<$在查询中c $ c> .append（）否则你会覆盖：

BasicDBObject query = new BasicDBObject();
query.put("country", "New Zealand");
query.append("regions.region", "Waikato");

BasicDBObject update = new BasicDBObject()
    .append("$inc", new BasicDBObject().append("regions.$.size", 145));

collection.update(query, update, true, false);

基本上看起来像这样（明智的）：

Basically looks like this ( shell wise ) :

collection.update(
    { "country": "New Zealand", "regions.region": " "Waikato" },
    { "$inc": regions.$.size": 145 },
    true,
    false
)

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