node.js 使用 Mongoose 从 MongoDB 文档中删除一个键
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/4486926/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Delete a key from a MongoDB document using Mongoose
提问by Daniel Beardsley
I'm using the MongooseLibrary for accessing MongoDB with node.js
我正在使用Mongoose库通过 node.js 访问 MongoDB
Is there a way to remove a key from a document? i.e. not just set the value to null, but remove it?
有没有办法从文档中删除密钥？即不只是将值设置为空，而是将其删除？
User.findOne({}, function(err, user){
//correctly sets the key to null... but it's still present in the document
user.key_to_delete = null;
// doesn't seem to have any effect
delete user.key_to_delete;
user.save();
});
回答by staackuser2
In early versions, you would have needed to drop down the node-mongodb-native driver. Each model has a collection object that contains all the methods that node-mongodb-native offers. So you can do the action in question by this:
在早期版本中，您需要删除 node-mongodb-native 驱动程序。每个模型都有一个集合对象，其中包含 node-mongodb-native 提供的所有方法。因此，您可以通过以下方式执行相关操作：
User.collection.update({_id: user._id}, {$unset: {field: 1 }});
Since version 2.0 you can do:
从 2.0 版开始，您可以执行以下操作：
User.update({_id: user._id}, {$unset: {field: 1 }}, callback);
And since version 2.4, if you have an instance of a model already you can do:
从 2.4 版开始，如果您已经有一个模型实例，您可以执行以下操作：
doc.field = undefined;
doc.save(callback);
回答by deedubs
You'll want to do this:
你会想要这样做：
User.findOne({}, function(err, user){
user.key_to_delete = undefined;
user.save();
});
回答by Noushad
I use mongoose and using any of the above functions did me the requirement. The function compiles error free but the field would still remain.
我使用猫鼬并使用上述任何功能满足我的要求。该函数编译无错误，但该字段仍将保留。
user.set('key_to_delete', undefined, {strict: false} );
did the trick for me.
帮我解决了这个问题。
回答by Andrew Orsich
回答by Luc
Could this be a side problem like using
这可能是一个附带问题，例如使用
function (user)
instead of
代替
function(err, user)
for the find's callback ? Just trying to help with this as I already had the case.
对于 find 的回调？只是想帮助解决这个问题，因为我已经有了这个案例。
回答by petarr
Mongoose document is NOT a plain javascript object and that's why you can't use delete operator.(Or unsetfrom 'lodash' library).
Mongoose 文档不是普通的 javascript 对象，这就是您不能使用 delete 运算符的原因。（或unset来自“lodash”库）。
Your options are to set doc.path = null || undefined or to use Document.toObject() method to turn mongoose doc to plain object and from there use it as usual. Read more in mongoose api-ref: http://mongoosejs.com/docs/api.html#document_Document-toObject
您的选择是设置 doc.path = null || undefined 或使用 Document.toObject() 方法将 mongoose doc 转换为普通对象，然后照常使用它。在 mongoose api-ref 中阅读更多内容：http: //mongoosejs.com/docs/api.html#document_Document-toObject
Example would look something like this:
示例如下所示：
User.findById(id, function(err, user) {
if (err) return next(err);
let userObject = user.toObject();
// userObject is plain object
});
回答by Milad ranjbar
the problem with all of these answers is that they work for one field. for example let's say i want delete all fields from my Document if they were an empty string "".
First you should check if field is empty string put it to $unset:
所有这些答案的问题在于它们适用于一个领域。例如，假设我想从我的文档中删除所有字段，如果它们是空字符串""。首先，您应该检查字段是否为空字符串将其放入$unset：
function unsetEmptyFields(updateData) {
const $unset = {};
Object.keys(updatedData).forEach((key) => {
if (!updatedData[key]) {
$unset[key] = 1;
delete updatedData[key];
}
});
updatedData.$unset = $unset;
if (isEmpty(updatedData.$unset)) { delete updatedData.$unset; }
return updatedData;
}
function updateUserModel(data){
const updatedData = UnsetEmptyFiled(data);
const Id = "";
User.findOneAndUpdate(
{ _id: Id },
updatedData, { new: true },
);
}
回答by Bivin Vinod
if you want to remove a key from collection try this method. this worked for me
如果你想从集合中删除一个键，试试这个方法。这对我有用
db.getCollection('myDatabaseTestCollectionName').update({"FieldToDelete": {$exists: true}}, {$unset:{"FieldToDelete":1}}, false, true);
回答by Jeisson Valderrama
Try:
尝试：
User.findOne({}, function(err, user){
// user.key_to_delete = null; X
`user.key_to_delete = undefined;`
delete user.key_to_delete;
user.save();
});
回答by Joel Esperanza
you can use delete user._doc.key
您可以使用删除 user._doc.key
