Question

在MongoDB 2.4中使用本机Nodejs驱动程序并尝试从嵌入在数组中的文档中删除属性。例如。如何从gym grades gym中562e7c1ae6c3e8ce29abfe05数组中嵌入的所有文档中删除{ "_id" : ObjectId("562abaaffb5870b8fb9dca3f"), "grades" : [ { "_id" : ObjectId("562e7bbe70ee82bb290192bd"), "discipline" : "55aae5b7848b9c8bf4ecbb5c", "grade" : "55aae5b7848b9c8bf4ecbb4c", "gym" : "562e7c1ae6c3e8ce29abfe06", "registeredOn" : ISODate("2015-10-26T19:15:10.565Z") }, { "discipline" : "55aae5b7848b9c8bf4ecbb5c", "grade" : "55aae5b7848b9c8bf4ecbb4d", "gym" : "562e7c1ae6c3e8ce29abfe05", "registeredOn" : ISODate("2015-10-26T19:17:08.603Z"), "_id" : ObjectId("562e7c34e6c3e8ce29abfe06") }, { "discipline" : "55aae5b7848b9c8bf4ecbb5c", "grade" : "55aae5b7848b9c8bf4ecbb4d", "gym" : "562e7c1ae6c3e8ce29abfe05", "registeredOn" : ISODate("2015-10-26T19:17:08.603Z"), "_id" : ObjectId("562e7c34e6c3e8ce29abfe07") } ], }, { "_id" : ObjectId("562abaaffb5870b8fb9dca3f"), "grades" : [ { "_id" : ObjectId("562e7bbe70ee82bb290192bd"), "discipline" : "55aae5b7848b9c8bf4ecbb5c", "grade" : "55aae5b7848b9c8bf4ecbb4c", "gym" : "562e7c1ae6c3e8ce29abfe07", "registeredOn" : ISODate("2015-10-26T19:15:10.565Z") }, { "discipline" : "55aae5b7848b9c8bf4ecbb5c", "grade" : "55aae5b7848b9c8bf4ecbb4d", "gym" : "562e7c1ae6c3e8ce29abfe05", "registeredOn" : ISODate("2015-10-26T19:17:08.603Z"), "_id" : ObjectId("562e7c34e6c3e8ce29abfe06") } ], }属性？所以从这个：

{
    "_id" : ObjectId("562abaaffb5870b8fb9dca3f"),
    "grades" : [
        {
            "_id" : ObjectId("562e7bbe70ee82bb290192bd"),
            "discipline" : "55aae5b7848b9c8bf4ecbb5c",
            "grade" : "55aae5b7848b9c8bf4ecbb4c",
            "gym" : "562e7c1ae6c3e8ce29abfe06",
            "registeredOn" : ISODate("2015-10-26T19:15:10.565Z")
        },
        {
            "discipline" : "55aae5b7848b9c8bf4ecbb5c",
            "grade" : "55aae5b7848b9c8bf4ecbb4d",
            "registeredOn" : ISODate("2015-10-26T19:17:08.603Z"),
            "_id" : ObjectId("562e7c34e6c3e8ce29abfe06")
        },
        {
            "discipline" : "55aae5b7848b9c8bf4ecbb5c",
            "grade" : "55aae5b7848b9c8bf4ecbb4d",
            "registeredOn" : ISODate("2015-10-26T19:17:08.603Z"),
            "_id" : ObjectId("562e7c34e6c3e8ce29abfe07")
        }
    ],
},
{
    "_id" : ObjectId("562abaaffb5870b8fb9dca3f"),
    "grades" : [
        {
            "_id" : ObjectId("562e7bbe70ee82bb290192bd"),
            "discipline" : "55aae5b7848b9c8bf4ecbb5c",
            "grade" : "55aae5b7848b9c8bf4ecbb4c",
            "gym" : "562e7c1ae6c3e8ce29abfe07",
            "registeredOn" : ISODate("2015-10-26T19:15:10.565Z")
        },
        {
            "discipline" : "55aae5b7848b9c8bf4ecbb5c",
            "grade" : "55aae5b7848b9c8bf4ecbb4d",
            "registeredOn" : ISODate("2015-10-26T19:17:08.603Z"),
            "_id" : ObjectId("562e7c34e6c3e8ce29abfe06")
        }
    ],
}

我需要这个：

"_id" : ObjectId("562e7c34e6c3e8ce29abfe07")

下面的查询将仅删除id为我指定的第一个匹配文档。但是，562e7c1ae6c3e8ce29abfe05的第二个文档仍然具有健身房属性multi。 collections.users.update({ "grades.gym": "562e7c1ae6c3e8ce29abfe05" }, { $unset: { "grades.$.gym": "562e7c1ae6c3e8ce29abfe05" } }, { multi: true })似乎是多余的，所以有没有办法删除我指定id的所有健身房属性？

let x:Double = 72.535
var xdp:Int = 0

if let decimalString = String(x).componentsSeparatedByString(".").last, let decimal = Int(decimalString) {
    xdp = decimal   // 535
}

Answer 1

最好使用 .find() 来返回光标，使用 .each() 方法对其进行迭代，以访问匹配的集合中的每个文档条件，从而获取数组字段，删除匹配条件的属性并更新文档，如下所示：

collection.find({ "grades.gym": "562e7c1ae6c3e8ce29abfe05" }).each(function(err, doc){
    // handle err
    var new_grades = doc.grades.map(function (grade){ 
        if (grade.gym == "562e7c1ae6c3e8ce29abfe05") { delete grade.gym; }
        return grade;
    });

    collection.update({ "_id": doc._id },{ "$set": { "grades": new_grades }});
});

如何从MongoDB 2.4中的数组内部的文档中删除属性

1 个答案: