使用 Mongoose 从 MongoDB 文档中删除键

发布于 2024-10-08 02:21:49 字数 433 浏览 1 评论 0原文

我正在使用 Mongoose 库通过 node.js 访问 MongoDB

有没有办法删除文档中的密钥？即不只是将值设置为 null，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();
});

原文

I'm using the Mongoose Library for accessing MongoDB with node.js

Is there a way to remove a key from a document? i.e. not just set the value to null, but remove it?

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();
});

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隐诗 2024-10-15 02:21:49

在早期版本中，您需要下拉 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 }});

从版本 2.0 开始，您可以执行以下操作：

User.update({_id: user._id}, {$unset: {field: 1 }}, callback);

从版本 2.4 开始，如果您已经有模型实例，则可以执行以下操作：

doc.field = undefined;
doc.save(callback);

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:

User.collection.update({_id: user._id}, {$unset: {field: 1 }});

Since version 2.0 you can do:

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:

doc.field = undefined;
doc.save(callback);

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迟到的我 2024-10-15 02:21:49

你会想要这样做：

User.findOne({}, function(err, user){
  user.key_to_delete = undefined;
  user.save();
});

You'll want to do this:

User.findOne({}, function(err, user){
  user.key_to_delete = undefined;
  user.save();
});

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薔薇婲 2024-10-15 02:21:49

我使用猫鼬并使用上述任何功能满足了我的要求。该函数编译时没有错误，但该字段仍然保留。

user.set('key_to_delete', undefined, {strict: false} );

为我成功了。

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.

user.set('key_to_delete', undefined, {strict: false} );

did the trick for me.

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皇甫轩 2024-10-15 02:21:49

在 mongo 语法中，要删除某些键，您需要执行以下操作：

{ $unset : { field : 1} }

在 Mongoose 中似乎也是如此。

编辑

检查此示例。

At mongo syntax to delete some key you need do following:

{ $unset : { field : 1} }

Seems at Mongoose the same.

Edit

Check this example.

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木格 2024-10-15 02:21:49

如果您想从集合中删除密钥，请尝试此方法。

 db.getCollection('myDatabaseTestCollectionName').update({"FieldToDelete": {$exists: true}}, {$unset:{"FieldToDelete":1}}, false, true);

if you want to remove a key from collection try this method.

 db.getCollection('myDatabaseTestCollectionName').update({"FieldToDelete": {$exists: true}}, {$unset:{"FieldToDelete":1}}, false, true);

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地狱即天堂 2024-10-15 02:21:49

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();
});

Try:

User.findOne({}, function(err, user){
  // user.key_to_delete = null; X
  `user.key_to_delete = undefined;`

  delete user.key_to_delete;

  user.save();
});

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好多鱼好多余 2024-10-15 02:21:49

这可能是一个附带问题，例如使用

function (user)

而不是

function(err, user)

查找的回调吗？只是想帮忙解决这个问题，因为我已经遇到过这种情况。

Could this be a side problem like using

function (user)

instead of

function(err, user)

for the find's callback ? Just trying to help with this as I already had the case.

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美煞众生 2024-10-15 02:21:49

Mongoose 文档不是普通的 javascript 对象，这就是为什么您不能使用删除运算符。（或从“lodash”库中取消设置）。

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，然后像往常一样使用它。
在 mongoose api-ref 中阅读更多内容：
http://mongoosejs.com/docs/api.html#document_Document-toObject

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
});

Mongoose document is NOT a plain javascript object and that's why you can't use delete operator.(Or unset from 'lodash' library).

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

Example would look something like this:

User.findById(id, function(err, user) {
    if (err) return next(err);
    let userObject = user.toObject();
    // userObject is plain object
});

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长途伴 2024-10-15 02:21:49

所有这些答案的问题在于它们只适用于一个领域。例如，假设我想删除文档中的所有字段（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 },
    );
}

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 :

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 },
    );
}

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