id和_id在mongoose有什么区别？ [英] What is the difference between id and _id in mongoose?

问题描述

mongoose中的 _id 和 id 之间有什么区别？哪个更适合引用？

What is the difference between _id and id in mongoose? Which is better for referencing?

推荐答案

文档：

Mongoose默认为每个模式分配一个id虚拟getter
它返回文档_id字段强制转换为一个字符串，或者在
的ObjectIds及其hexString的情况下。

Mongoose assigns each of your schemas an id virtual getter by default which returns the documents _id field cast to a string, or in the case of ObjectIds, its hexString.

因此，基本上， id getter返回文档的 _id 默认情况下是文档，并且默认类型为 ObjectId ）。

So, basically, the id getter returns a string representation of the document's _id (which is added to all MongoDB documents by default and have a default type of ObjectId).

上下文（即，你想要 ObjectId 或字符串）。例如，如果比较 id 的字符串可能更好，因为 ObjectId '不会通过平等测试，除非它们是相同的实例（不管它们代表什么值）。

Regarding what's better for referencing, that depends entirely on the context (i.e., do you want an ObjectId or a string). For example, if comparing id's, the string is probably better, as ObjectId's won't pass an equality test unless they are the same instance (regardless of what value they represent).

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