如何从 MongoDb 对象中删除属性？
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How to remove attribute from MongoDb Object?
提问by johndoe
I have added MiddleName attribute to my Customer object. Customer is a simple Object() instance. I want to remove this attribute from my object. How can I do that? I am using MongoDb interactive Console.
我已将 MiddleName 属性添加到我的 Customer 对象。Customer 是一个简单的 Object() 实例。我想从我的对象中删除这个属性。我怎样才能做到这一点？我正在使用 MongoDb 交互式控制台。
回答by Telmo Dias
You should use the $unset modifier while updating:
您应该在更新时使用 $unset 修饰符：
To delete: (most recent syntax)https://docs.mongodb.com/manual/reference/method/db.collection.update/
删除：（最新语法）https://docs.mongodb.com/manual/reference/method/db.collection.update/
db.collection.update(
{},
{
$unset : {
"properties.service" : 1
}
},
{
multi: true
}
);
Updated thanks to Xavier Guihotcomment!
感谢Xavier Guihot评论更新！
To delete: (only left for reference of the old syntax)
删除：（仅供参考旧语法）
// db.collection.update( criteria, objNew, upsert, multi )
// db.collection.update(criteria, objNew, upsert, multi )
db.collection.update(
{
"properties.service" : {
$exists : true
}
},
{
$unset : {
"properties.service" : 1
}
},
false,
true
);
To verify they have been deleted you can use:
要验证它们已被删除，您可以使用：
db.collection.find(
{
"properties.service" : {
$exists : true
}
}
).count(true);
Remember to use the multi option as true if you want to update multiple records. In my case I wanted to delete the properties.service attribute from all records on this collection.
如果要更新多个记录，请记住将 multi 选项设为 true。在我的例子中，我想从这个集合的所有记录中删除 properties.service 属性。
