我有一个集合，其中每个文档看起来像这样：
{
_id: 'dev_id:datetime_hour',
data: {
0: {
0: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
1: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
2: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
59: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}
},
1: {
0: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
1: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
2: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
59: {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}
}
}
我在这里简化了它，但基本思路是：传感器数据每秒存储一次，但按小时捆绑在一起。 ＆＃39;数据＆＃39;字段按分钟索引，每分钟索引除以秒。因此，整个小时的数据将在嵌套数据字段中产生3600个条目。例如，要获取第一分钟和第三秒的传感器数据，我可以直接访问该对象：data.1.3。
此类架构为recommended for storing time series data by MongoDB。
我的聚合管道的第1阶段如下所示：
db.raw_electric.aggregate(
[
// Stage 1
{
$match: {
_id: { $regex: /^r10a:/ },
datehour: {$gte: ISODate("2016-09-21T17:00:00"), $lte: ISODate("2016-09-21T19:00:00")}
}
}
]
);
是否可以放松＆＃39;文档 - 类似于你如何解开一个数组，以便我可以暴露一个对象的每个嵌套层？
答案 0 :(得分：2)
您应该按照以下方式创建架构：
{
_id: 'dev_id:datetime_hour',
data: [{
name: '0',
info: [{}]
}]
}
ieyour数据应该是一个对象数组。从该数组中，您可以使用其索引获取任何对象。
{
_id: 'dev_id:datetime_hour',
data: [{
name: '0',
info: [{
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}, {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}, {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}, {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}],
{
name: '1',
info: [{
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}, {
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}
}]
}
}]
}
答案 1 :(得分：0)
好像你有多个嵌套对象。在您的情况下，如果您考虑将要取消的总数组获得1小时数据，它将是：1 * 60 * 60 = 3600。
此外，多个嵌套不必要地增加了检索和更新数据的复杂性。
您需要更扁平的结构，可以通过以下方式实现： -
为每分钟创建单独的文档。结构会像 -
{
_id: ObjectId('');
hour: 1,
minute: 1
seconds: [
{
item: 0,
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
{
item: 1,
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}
]
},
{
_id: ObjectId('');
hour: 1,
minute: 2
seconds: [
{
item: 0,
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
},
{
item: 1,
voltage_a: float,
voltage_b: float,
voltage_c: float,
current_a: float,
current_b: float,
current_c: float,
current_n: float,
active_power_a: float,
active_power_b: float,
active_power_c: float,
total_active_power: float
}
]
}
此结构可能随后增加文档数量。但是会降低查询所涉及的复杂性。此外，通过有效的索引，可以保持性能。 （对于大数据，您还应该查看分片）。