如何在mongoDb

Question

这是我的文档结构：

{
"_id" : ObjectId("5841eba5d3693034c49da7d7"),
"Key" : "01041655",
"matchingKey" : "01041655",
"brand" : "Brand",
"name" : "Product Name",
"availabilities" : [ 
    {
        "data1" : [ 
            {
                "number_a" : null,
                "number_b" : "4.5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }, 
            {
                "number_a" : null,
                "number_b" : "5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }, 
            {
                "number_a" : null,
                "number_b" : "5.5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }
        ]
    }, 
    {
        "data2" : [ 
            {
                "number_a" : null,
                "number_b" : "4.5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }, 
            {
                "number_a" : null,
                "number_b" : "5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }
        ]
    }
]
}

我不确定这是否是最佳方式，所以如果有更好的方法，请告诉我。我的问题是：如何删除数组data1或data2。在Java中最好的方法是什么？我当前的Java代码如下所示：

Document array = new Document("availabilities", dataKey);
Document updateSet = new Document("$unset", array);
prodCollection.updateMany(eq("matchingKey", matchingKey), updateSet);

但是此代码会删除可用性中的所有文档。

UPDATE1： 我改变了文档结构：

{
"_id" : ObjectId("5841eba5d3693034c49da7d7"),
"Key" : "01041655",
"matchingKey" : "01041655",
"brand" : "Brand",
"name" : "Product Name",
"availabilities" :  {
        "data1" : [ 
            {
                "number_a" : null,
                "number_b" : "4.5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }, 
            {
                "number_a" : null,
                "number_b" : "5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }, 
            {
                "number_a" : null,
                "number_b" : "5.5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }
        ],         
        "data2" : [ 
            {
                "number_a" : null,
                "number_b" : "4.5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }, 
            {
                "number_a" : null,
                "number_b" : "5",
                "number_c" : null,
                "number_d" : null,
                "amount" : 0,
                "lastCheck" : "2016-12-02T22:46:13.393+01:00"
            }
        ]
    }
}

现在我可以在mongodb中删除类似的特定数组：

db.products.update({"matchingKey":'01041655'},{$unset: {"availabilities.data1":1}});

我怎么能用Java做到这一点？我这样试过：

Document array = new Document("availabilities.data1", 1);
Document updateSet = new Document("$unset", array);
prodCollection.updateOne(eq("matchingKey", matchingKey), updateSet);

但它仍会删除所有数组。

Answer 1

我对$ set运算符产生了误解。它用新的数据替换旧数据。因此，我不需要删除该阵列。我只需要在Java中使用$ set：

Document availDoc = new Document("availabilities."+key, availabilities);
Document updateSet = new Document("$set", availDoc);
prodCollection.updateOne(eq("matchingKey", matchingKey), updateSet);