java - 如何更新mongo中的嵌入文档？

Question

我在 mongo 数据库中有以下文档。

  { "_id" : ObjectId("50656f33a4e82d3f98291eff"), 
     "description" : "gdfgdfgdfg",
     "menus" : [    
               {    
                 "name" : "gdfgdfgdfg",     
                  "description" : "dfgdgd",     
                  "text" : "dfgdfg",    
                  "key" : "2",  
                  "onSelect" : "yyy",   
                  "_id" : ObjectId("50656f3ca4e82d3f98291f00") 
              }, 
               {    
                 "name" : "rtytry",     
                  "description" : "gffhf",  
                  "text" : "dfgdfg",    
                  "key" : "2",  
                  "onSelect" : "yyy",   
                  "_id" : ObjectId("50656f3ca4e82d3f98281f00") 
              }],
      "select":"ffdfgd"
   }

我想要自动更新菜单 {
“名称”:“gdfgdfgdfg”，
“描述”:“dfgdgd”，
“文本”:“dfgdfg”，
“键”:“2”，
"onSelect": "yyy",
“_id”:ObjectId(“50656f3ca4e82d3f98291f00”) }

我尝试使用以下代码:

         BasicDBObject query = new BasicDBObject("_id", new ObjectId("50656f33a4e82d3f98291eff"));

         BasicDBObject update = new BasicDBObject("_id", ObjectId("50656f3ca4e82d3f98291f00"));

         BasicDBObject updateCommand = new BasicDBObject("$set", new BasicDBObject("menus", update));

         collection.update(query, updateCommand);

我得到的结果是

  { "_id" : ObjectId("50656f33a4e82d3f98291eff"), 
 "description" : "gdfgdfgdfg",
 "menus" :    
           {    
             "name" : "gdfgdfgdfg",     
              "description" : "dfgdgd",     
              "text" : "dfgdfg",    
              "key" : "2",  
              "onSelect" : "yyy",   
              "_id" : ObjectId("50656f3ca4e82d3f98291f00") 
          },
  "select":"ffdfgd"

}

但我想在同一个嵌入文档中进行更新。

任何人指导我......提前致谢

Answer 1

好吧，在读了几遍之后(英语......)我想我现在明白了。

您想要使用 _id 50656f3ca4e82d3f98291f00 访问子文档:

{
"name" : "gdfgdfgdfg",
"description" : "dfgdgd",
"text" : "dfgdfg",
"key" : "2",
"onSelect" : "yyy",
"_id" : ObjectId("50656f3ca4e82d3f98291f00") 
} 

您遇到的第一个问题是您的代码仅将 menus 字段设置为此对象。您需要的是位置运算符。所以你需要做一个点符号查找(警告我的Java有点生疏):

query.append("menus._id", new ObjectId("50656f3ca4e82d3f98291f00"));

然后使用该位置运算符更新位置:

BasicDBObject update_document = new BasicDBObject("menus.$.name", my_new_subdocument.name);
update_document.append("menus.$.description", my_new_subdocument.description);
// All the other fields

BasicDBObject updateCommand = new BasicDBObject("$set", update_document);

希望这能解决问题。