sort - mongodb 结果集默认顺序标准

Question

collection有多个文档，如果查询结果没有进行sort排序，那么find()的结果集的默认顺序是以什么为标准的？

Answer 1

Basically the order in the file (so it is often the order of insert).

To be cautious, you can think of it as disorder. If you need a specific order, you still have to use sort.

Reference:

http://docs.mongodb.org/manual/reference/glossary/#term-natural-order

Answer 2

When mongodb inserts data, it will add the "_id" attribute by default and create an index with it. So it's the order of insertion.