如何在mongoDB中删除数组内的一个数组？

Question

我需要移除一个嵌套数组，但只能找到删除非嵌套数组元素的查询方法。如何删除这个嵌套数组内特定元素（ID）？我的查询有什么问题导致出错？是否存在更好的解决方案，而无需使用嵌套数组？

文档

{
    "_id" : "8d127e9ca7178f900dc4953725188da9",
    "dataCriacao" : "2015-05-11T09:10:56.251-0300",
    "pecas" : [ 
        {
            "id" : "49919187a3c4871923dcda506eef5f73",
            "path" : null,
            "nome" : "Whirlpool_LinhaBranca_Positivo_CanaisdeAfinidade_SuperBanner_-.swf",
            "pathOriginal" : "1401 Pecas Midia Grafica_v2/Whirlpool_LinhaBranca_Positivo_CanaisdeAfinidade_SuperBanner_-.swf",
            "imagem" : null,
            "comentarios" : [ 
                {
                    "id" : "c1c586be8ded3d044f96fccc18473cf8",
                    "comentario" : "teste comentario",
                    "horario" : "2015-05-11T09:11:55.399-0300"
                }, 
                {
                    "id" : "dfc10dc2029ad93cf9585a3ecb3ebe51",
                    "comentario" : "teste comentario",
                    "horario" : "2015-05-11T09:11:55.418-0300"
                }, 
                {
                    "id" : "3ef39b18f6d7dc45d6d6f7ccb27a2e10",
                    "comentario" : "teste comentario2",
                    "horario" : "2015-05-11T09:12:11.124-0300"
                }, 
                {
                    "id" : "72b88be895da0b9b7f66c7be55d3ae3b",
                    "comentario" : "teste comentario2",
                    "horario" : "2015-05-11T09:12:11.140-0300"
                }
            ]
        }, 
        {
            "id" : "b22b488ed7302995fa2971d69f425516",
            "path" : null,
            "nome" : "Whirlpool_LinhaBranca_Positivo_DeskMedia_Widget_-.jpg",
            "pathOriginal" : "1401 Pecas Midia Grafica_v2/Whirlpool_LinhaBranca_Positivo_DeskMedia_Widget_-.jpg",
            "imagem" : null
        }, 
        {
            "id" : "846bf4984f533b46de83b0fea1b1e06d",
            "path" : null,
            "nome" : "Whirlpool_LinhaBranca_BuscaDescontos_Homepage_Cupom_-.jpg",
            "pathOriginal" : "1401 Pecas Midia Grafica_v2/Whirlpool_LinhaBranca_BuscaDescontos_Homepage_Cupom_-.jpg",
            "imagem" : null
        }, 
        {
            "id" : "5574d989005d89f9181ae1d4acffd7b3",
            "path" : null,
            "nome" : "Whirlpool_LinhaBranca_BuscaDescontos_Homepage_SuperBanner_-.swf",
            "pathOriginal" : "1401 Pecas Midia Grafica_v2/Whirlpool_LinhaBranca_BuscaDescontos_Homepage_SuperBanner_-.swf",
            "imagem" : null
        }, 
        {
            "id" : "3cddcc834c466e945fe5a97ecb75cbf3",
            "path" : null,
            "nome" : "Whirlpool_LinhaBranca_Positivo_DeskMedia_Widget.jpg",
            "pathOriginal" : "1401 Pecas Midia Grafica_v2/Whirlpool_LinhaBranca_Positivo_DeskMedia_Widget.jpg",
            "imagem" : null
        }, 
        {
            "id" : "cebfef8ed985551560cfd72ac72535dd",
            "path" : null,
            "nome" : "Whirlpool_LinhaBranca_Zoom_Newsletter_Destaque_-.jpg",
            "pathOriginal" : "1401 Pecas Midia Grafica_v2/Whirlpool_LinhaBranca_Zoom_Newsletter_Destaque_-.jpg",
            "imagem" : null
        }, 
        {
            "id" : "60a64c5154c79379a6c1c6cb1685ead6",
            "path" : null,
            "nome" : "Whirlpool_LinhaBranca_Positivo_CanaisdeAfinidade_Retangulo_-.swf",
            "pathOriginal" : "1401 Pecas Midia Grafica_v2/Whirlpool_LinhaBranca_Positivo_CanaisdeAfinidade_Retangulo_-.swf",
            "imagem" : null
        }
    ],
    "validacaoId" : "55509b6dccf2d4a2f3545fcb",
    "email" : "[e-mail]",
    "instancia" : "sofist",
    "tipo" : "3"
}

查询1

db.getCollection('validacao_permalinks').update(
    {_id: "8d127e9ca7178f900dc4953725188da9"}, 
    {
        $pull: { "pecas.comentarios": {
            $elemMatch: {id:"c1c586be8ded3d044f96fccc18473cf8"}
            }
        }
     }
 )

错误

cannot use the part (pecas of pecas.comentarios) to traverse the element

- Daniela Morais

Answer 1

这是解决方案，请尝试：

db.getCollection('validacao_permalinks').update(
    {'pecas.comentarios.id': "c1c586be8ded3d044f96fccc18473cf8"}, 
    {
        $pull: { 'pecas.$.comentarios': {
            "id":"c1c586be8ded3d044f96fccc18473cf8"}            
        }
     }
 )

这段代码 {'pecas.comentarios.id': "c1c586be8ded3d044f96fccc18473cf8"} 将会找到文档，

然后$pull将从数组中删除该文档。

以下是 MongoDB Remove 功能的其他参考资料：

http://docs.mongodb.org/manual/reference/operator/update/pull/

- Satish Shinde

Answer 2

这是我的工作示例：

Floors是一个包含房间数组的集合，此查询将删除指定ID的“room”对象：

db.floors.update(
   { _id: ObjectId("547dc92e85fca4dc0b0c6f26") },
   {
        $pull: { rooms: {
            _id: ObjectId("547dc94685fca4dc0b0c6f29")
            } }
   },
   {upsert:false }
)
db.floors.find()

- Mike