计算某种类型的文档（之前针对用户进行过滤）
文件（伪，rev和id省略）：
{
"type": 1,
"username": "aron",
"data": { ... }
}
{
"type": 1,
"username": "bob",
"data": { ... }
}
{
"type": 1,
"username": "steve",
"data": { ... }
}
{
"type": 1,
"username": "steve",
"data": { ... }
}
{
"type": 2,
"username": "steve",
"data": { ... }
}
{
"type": 3,
"username": "steve",
"data": { ... }
}
{
"type": 3,
"username": "steve",
"data": { ... }
}
{
"type": 3,
"username": "steve",
"data": { ... }
}
我想知道，steve有多少个1/2/3类型的文件。
查看：
count: {
map: function (doc) {
emit([doc.username, doc.type], 1);
}
reduce: function (key, values, rereduce) {
return sum(values);
}
}
现在我要求
/database/_design/myDesign/_view/count?key=["steve",1] // result: 2
/database/_design/myDesign/_view/count?key=["steve",2] // result: 1
/database/_design/myDesign/_view/count?key=["steve",3] // result: 3
这个工作得很好。
为了让事情变得更聪明，我想知道我是否可以在一个视图中查询它？
有没有一种方法可以统计一个视图中未知类型文档的数量？
Documents (pseudo, rev and id omitted):
{
"type": 1,
"username": "aron",
"data": { ... }
}
{
"type": 1,
"username": "bob",
"data": { ... }
}
{
"type": 1,
"username": "steve",
"data": { ... }
}
{
"type": 1,
"username": "steve",
"data": { ... }
}
{
"type": 2,
"username": "steve",
"data": { ... }
}
{
"type": 3,
"username": "steve",
"data": { ... }
}
{
"type": 3,
"username": "steve",
"data": { ... }
}
{
"type": 3,
"username": "steve",
"data": { ... }
}
I want to know, how many documents of type 1/2/3 steve has.
View:
count: {
map: function (doc) {
emit([doc.username, doc.type], 1);
}
reduce: function (key, values, rereduce) {
return sum(values);
}
}
Now I request
/database/_design/myDesign/_view/count?key=["steve",1] // result: 2
/database/_design/myDesign/_view/count?key=["steve",2] // result: 1
/database/_design/myDesign/_view/count?key=["steve",3] // result: 3
This works perfectly well.
To smart things up, I was wondering if I can query that in one view?
Is there a way to count the number of documents of unknown number of types in one view?
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您可以使用这样的正文发布到您的视图；
另外，尝试使用“_sum”作为你的reduce函数，它将在Erlang中本地运行，并且应该比在Javascript中快几倍。
You can POST to your view with a body like this;
Also, try using "_sum" as your reduce function, it will run natively in Erlang and should be several times faster than doing it in Javascript.
您可以执行范围查询来实现此目的：
这将为
["steve",1]和["steve",3]之间的每个键获取一行。您可以根据实际类型调整值0和3。例如，如果您的类型可以是任何标量值，则可以使用["steve",null]和["steve",{}]作为范围边界。You can perform a range query to achieve this:
This will fetch one line for every key between
["steve",1]and["steve",3]inclusive. You can adjust values0and3according to what your types can actually be. For instance, if your types can be any scalar value, you can use["steve",null]and["steve",{}]as the range boundaries.