如何使用 findOne 查询 mongodb 并排除数组中的一些嵌套字段
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【中文标题】如何使用 findOne 查询 mongodb 并排除数组中的一些嵌套字段【英文标题】：how to query mongodb using findOne and exclude some nested fields in array 【发布时间】：2021-11-26 12:31:20 【问题描述】：虽然我使用过 mysql，但我是 MongoDB 新手。
我的用户集合具有以下形状的用户数据 -
我正在创建api in nodejs，它会获取给定用户的全部数据，但应该排除每种数据类型中的transactions 字段。
我的获取数据 api：localhost:5000/api/users/id/:id/data
请帮我写查询。我已经创建了 api 来获取所有用户、创建用户、更新用户，但我只坚持这个。我也尝试过使用聚合，但它会返回包括交易在内的整个数据。我的尝试-
getUserData = async (req, res) =>
const id = req.params;
try
const userData = await UserModel.findById(id).aggregate([
$project: "data.v.transactions": 0
]);
if (!userData ) res.status(400).json( success: false, message: `No data found` );
res.status(200).send(userData);
catch (error)
console.error(error);
res.status(400).send( status: false, error );
我在我的 nodejs 应用程序中使用 mongoose 包。
用户集合中的一个用户对象 --
"_id": "615d6a2afabf089b94a116e6",
"email": "john@doe.com",
"data":
"TYPE_1": [
"type": "type_1",
"transactions":
"endDate": "2020-09-17T14:25:33.440Z",
"startDate": "2019-04-11T11:39:57.153Z",
"transaction": [
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
]
,
"profile":
"full_name": "John Doe"
,
"summary":
"note": "Lorem Ipsum"
,
"type": "type_1",
"transactions":
"endDate": "2020-09-17T14:25:33.440Z",
"startDate": "2019-04-11T11:39:57.153Z",
"transaction": [
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
]
,
"profile":
"full_name": "John Doe"
,
"summary":
"note": "Lorem Ipsum"
,
"type": "type_1",
"transactions":
"endDate": "2020-09-17T14:25:33.440Z",
"startDate": "2019-04-11T11:39:57.153Z",
"transaction": [
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
]
,
"profile":
"full_name": "John Doe"
,
"summary":
"note": "Lorem Ipsum"
],
"TYPE_2": [
"type": "type_2",
"transactions":
"endDate": "2020-09-17T14:25:33.440Z",
"startDate": "2019-04-11T11:39:57.153Z",
"transaction": [
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
]
,
"profile":
"full_name": "John Doe"
,
"summary":
"note": "Lorem Ipsum"
,
"type": "type_2",
"transactions":
"endDate": "2020-09-17T14:25:33.440Z",
"startDate": "2019-04-11T11:39:57.153Z",
"transaction": [
"mode": "A",
"type": "AB",
"amount": "0"
]
,
"profile":
"full_name": "John Doe"
,
"summary":
"note": "Lorem Ipsum"
,
"type": "type_2",
"transactions":
"endDate": "2020-09-17T14:25:33.440Z",
"startDate": "2019-04-11T11:39:57.153Z",
"transaction": [
"mode": "A",
"type": "AB",
"amount": "0"
,
"mode": "A",
"type": "AB",
"amount": "0"
]
,
"profile":
"full_name": "John Doe"
,
"summary":
"note": "Lorem Ipsum"
]
,
"createdAt": "2021-10-06T09:19:39.378Z",
"updatedAt": "2021-10-06T09:19:39.378Z",
"__v": 0
【问题讨论】：
你想要得到什么结果？ @TobiasS。没有交易字段的集合中的整个用户对象。 【参考方案1】：不妨试试这个：
const userData = await UserModel.find(,
"data.TYPE_1.transactions" : 0,
"data.TYPE_2.transactions" : 0
)
【讨论】：
但我需要从每个类型中排除事务，而不仅仅是 Type_1 只有type_1和type_2吗？ @TobiasS。与其忽略您不想要的字段，不如选择您想要想要的字段。这样可以确保如果您添加新字段，您不会无意中选择它们。 Tobias，可以有很多种类型，我只是嘲笑了一下。 @MikeEason 请通过排除不需要的字段或仅选择想要的字段来提供通用解决方案。以上是关于如何使用 findOne 查询 mongodb 并排除数组中的一些嵌套字段的主要内容，如果未能解决你的问题，请参考以下文章
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