Developing a HTML5 offline storage solution for iOS/Android in 2011

Question

The problem:

I need a device agnostic (e.g. HTML5) solution for storing and querying 250,000+ rows of data offline on a phone or tablet type device (e.g

Answer 1

It worths to check out my open source library https://bitbucket.org/ytkyaw/ydn-db/wiki/Home

Javascript database module for Indexeddb, WebDatabase (WebSQL) and WebStorage (localStorage) storage mechanisms supporting version migration, advanced query and transaction.

Being NoSQL library, join is manual, but not impossible. There is already key joining algorithms build-in the library.