How to do pagination using range queries in MongoDB?

Question

I\'m probably missing something since I\'m still learning the ins and outs of MongoDB, but I need help with paging a collection.

I have a collection that has a lis

Answer 1

Since the collection I was paging had duplicate values I had to create a compound index on ProductName and id.

Create Compound Index

db.ProductGuideItem.ensureIndex({ ProductName:1, _id:1});

This solved my problem.
Reference: https://groups.google.com/d/msg/mongodb-user/3EZZIRJzW_A/oYH79npKZHkJ

Assuming you have these values:

{a:1, b:1}
{a:2, b:1}
{a:2, b:2}
{a:2, b:3}
{a:3, b:1}

So you do this for the range based pagination (page size of 2):

1st Page

find().sort({a:1, b:1}).limit(2)
{a:1, b:1}
{a:2, b:1}

2nd Page

find().min({a:2, b:1}).sort({a:1, b:1}).skip(1).limit(2)

{a:2, b:2}
{a:2, b:3}

3rd Page

find().min({a:2, b:3}).sort({a:1, b:1}).skip(1).limit(2)
{a:3, b:1}

Here are the docs for $min/max: http://www.mongodb.org/display/DOCS/min+and+max+Query+Specifiers

If you don't have duplicate values in your collection, you don't need to use min & max or create a compound index. You can just use $lt & $gt.