查找文档时如何防止MongoDB返回对象ID? [英] How to prevent MongoDB from returning the object ID when finding a document?
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问题描述
我在MongoDB中有以下文档...
I've the following document in MongoDB...
{
"_id" : ObjectId("531221cd960100960116b992"),
"username : "joe",
"address" : [
{
"zip" : "8000",
"city" : "Zurich"
},
{
"zip" : "6900",
"city" : "Lugano"
}
]
}
...并使用以下语句检索第二个地址:
... and to retrieve the second address I use the following statement:
db.users.find({ _id: ObjectId("531221cd960100960116b992") }, { addresses: { $slice: [0, 1] } } )
此方法有效,除了它还会返回对象ID:
This works except it also returns the object id:
{ "addresses" : [ { "zip" : "6900", "city" : "Lugano" } ], "_id" : ObjectId("531221cd960100960116b992") }
如何防止MongoDB返回对象ID?我知道我应该提供像_id : 0
这样的投影...但是在上面的表达式中应该放在哪里?我做了很多尝试...但是没有成功.
How do I prevent MongoDB from returning the object id? I know I should provide a projection like _id : 0
... but where should I put it in the expression above? I did a number of tries... but without success.
谢谢.
推荐答案
这与@hanleyhansen的答案完全相同,只是要告诉您可以将0与false互换使用,例如:
This is exactly the same as @hanleyhansen's answer, but just to let you know that you can use 0 interchangeably with false like:
db.users.find(
{ _id: ObjectId("531221cd960100960116b992")},
{ addresses: { $slice: [0, 1] } ,'_id': 0}
)
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