相关疑难解决方法(0)

尝试按照此处的示例过滤使用投影来排除_id._id仍然返回:

码

var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/db1";

MongoClient.connect(url, function (err, db) {
    if (err) throw err;
    var dbase = db.db("db1"); //here    

    dbase.collection("customers").find(
        {},
        {
            _id: 0

        }
        ).toArray(function(err, result) {
        if (err) throw err;
        console.log(result);
        db.close();
    });

});

结果仍然如下返回:

[{_id:5a2bb2d6ee48575cb54c4365,姓名:'John',地址:'Highway 71'},{_ id:5a2bb2d6ee48575cb54c436d,姓名:'Susan',地址:'One way 98'},.... {_ id:5a2bb2d6ee48575cb54c4371,name :'Chuck',地址:'Main Road 989'},{_ id:5a2bb2d6ee48575cb54c4372,名称:'Viola',地址:'Sideway 1633'}]

理论上_id不应该是返回的一部分.这有什么不对？

目前我正在编写一个查询，该查询显示具有特定注册号的卡车的信息，但不允许在我的查询中显示对象 ID。到目前为止，我能够获得所需的输出，但尽管在查询中输入了“_id”：0，但在查询期间对象 ID 仍然存在。

[询问]

db.transport.find(
    {
        $or:[
            {"TRUCK.registration":"PKR768"},
            {"TRUCK.registration":"PKR008"},
            {"TRUCK.registration":"SST005"},
            {"_id":0},
        ]
    }
).pretty()

[输出]

{
    "_id" : ObjectId("5fab387f48a75b7c08cedfe4"),
    "TRUCK" : {
        "registration" : "PKR008",
        "capacity" : "22000",
        "weight" : "8800",
        "status" : "AVAILABLE"
    }
}
{
    "_id" : ObjectId("5fab387f48a75b7c08cedfe5"),
    "TRUCK" : {
        "registration" : "PKR768",
        "capacity" : "1234",
        "weight" : "3000",
        "status" : "AVAILABLE"
    }
}
{
    "_id" : ObjectId("5fab387f48a75b7c08cedfe7"),
    "TRUCK" : {
        "registration" : "SST005",
        "capacity" : "12000",
        "weight" : "50000",
        "status" : "USED"
    }
}