In mongoDB what does it mean that find command returns a cursor?

Question

This is from a book I am reading:

Strictly speaking, the find() command returns a cursor to the returning documents. Therefore, to access the documents you’ll need to iterate the cursor. The find() command automatically returns 20 documents—if they’re available—after iterating the cursor 20 times.

I cannot understand what the author means. What is a cursor in MongoDB.

Possible duplicate of [What is a Cursor in MongoDB?](https://stackoverflow.com/questions/36766956/what-is-a-cursor-in-mongodb) — Explosion Pills, May 17 '18 at 17:20

score 0 · Accepted Answer · answered May 17 '18 at 17:28

There are many slightly different ways to process the result of a request:

Maybe you want to sort them
Maybe you want to limit the number of results
Maybe you want to skip items
Etc...

To allow you to do this in a convenient way, and offer a performant implementation, mongodb asks you to do things in two steps:

Speficy the request (filter and projection)
Then, tell what you want to do with the results (sort, skip, limit, etc...)

Step 1 returns the cursor.

The cursor has methods which allow you to specify what you want to do in step 2, and it also has methods which allow you to iterate on the result.

Results are actually retrived over time while you iterate. This allows to use reasonable amounts of system resources.

can you please explain with the example – Ashh May 17 '18 at 17:51 — Ashh, May 17 '18 at 17:51

In mongoDB what does it mean that find command returns a cursor?

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