mongo c驱动程序更新嵌套数组

Question

我想使用mongo c驱动程序更新单个文档中的嵌套数组。下面是一个例子测试文档：

{ 
    "_id" : ObjectId("562416504bacd3940b8b2d5c"), 
    "folder1" : [ 
    { 
     "folder_id" : "5624200d4bacd3940b8b2d62", 
     "some" : "data" 
    }, 
    { 
     "folder_id" : "562940084bacf60575d3b17e", 
     "some" : "data" 
    } 
    ], 
    "folder2" : [ 
    { 
     "folder_id" : "5627e20d4bacefccf4864e4e", 
     "some" : "data" 
    } 
    ] 
} 

我想通过这两个"folder1"和"folder2"迭代寻找匹配特定字符串（如：5624200d4bacd3940b8b2d62）任何"folder_id"。然后我希望从数组中删除整个元素。所以删除后我的文档应该看起来像：

{ 
    "_id" : ObjectId("562416504bacd3940b8b2d5c"), 
    "folder1" : [ 
    { 
     "folder_id" : "562940084bacf60575d3b17e", 
     "some" : "data" 
    } 
    ], 
    "folder2" : [ 
    { 
     "folder_id" : "5627e20d4bacefccf4864e4e", 
     "some" : "data" 
    } 
    ] 
} 

我知道如何修改文档中的单个元素，例如下面。但我还没有找到任何通过嵌套数组元素迭代的好例子。

update = BCON_NEW ("$set", "{","some_cool_key", BCON_UTF8 ("some cool data for key"),"}"); 
mongoc_collection_update (collection, MONGOC_UPDATE_NONE, query, update, NULL, &error); 

Answer 1

我想给John Moore @ ObjectRocket以帮助我。他提供了一个简单的一行BCON，它完全符合我的需求：

update = BCON_NEW ("$pull", "{", "folder1", "{", "folder_id", BCON_UTF8 ("5624200d4bacd3940b8b2d62"), "}", "}");