MongoDB $lookup 与 Mongoose 填充 [英] MongoDB $lookup vs Mongoose populate
问题描述
我看过这个和其他类似标题的问题，没有回答我的问题.
我正在阅读 mongoose 文档
<块引用>MongoDB 在版本中具有类似连接的 $lookup 聚合运算符 >=3.2.Mongoose 有一个更强大的替代方法，叫做 populate()，它可以让你引用其他集合中的文档.
mongoose 中的 populate() 如何工作，使其比 MongoDB 的 $lookup 更强大?
mongoose 不是一个帮助 nodejs 用户使用 mongodb 的工具.如果是这样，猫鼬如何拥有 MongoDB 没有的功能?像populate()?
mongoose 的 populate() 方法是否在幕后使用了 MongoDB 的 $lookup?
感谢 github 线程 由 Grégory NEUT 在问题的评论中分享我已经能够确定某些事实:
- Mongoose 的 populate() 方法在幕后没有使用 MongoDB 的 $lookup.它只是对数据库进行另一个查询.
- Mongoose 没有 MongoDB 没有的功能.
populate()只是进行两个或多个查询.
<块引用>
mongoose 中的 populate() 如何工作使其比MongoDB 的 $lookup?
在我看来，有些地方可以使用populate()，有些地方可以使用$lookup.对于更复杂的查询，聚合管道中的 $lookup 效果最好.
I have seen this and other similar titled questions, none answer my question.
I was going through the mongoose documentation where I read
MongoDB has the join-like $lookup aggregation operator in versions >= 3.2. Mongoose has a more powerful alternative called populate(), which lets you reference documents in other collections.
How does populate() in mongoose work that makes it more powerful than MongoDB's $lookup?
Isn't mongoose a tool that helps nodejs users work with mongodb. If so how can mongoose have functionalities that MongoDB does not? Like populate()?
Does mongoose's populate() method use MongoDB's $lookup behind the scenes?
Thanks to a github thread shared by Grégory NEUT in the question's comments I have been able to establish certain facts:
- Mongoose's populate() method does not use MongoDB's $lookup behind the scenes. It simply makes another query to the database.
- Mongoose does not have functionalities that MongoDB does not have.
populate()just makes two or more queries.
How does populate() in mongoose work that makes it more powerful than MongoDB's $lookup?
In my opinion, there are places to use populate() and others to use $lookup. For more complex queries $lookup in an aggregation pipeline would work best.
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