active record tutorials

Hi
   Can anybody give links to(ebooks,tutorials) understand
relations,callbacks and validations of Active Record more deeply

Sijo

There's the start of a set of related links here:
http://www.buildingwebapps.com/topic/73-active-record

There's some useful screencasts at Railscasts.com.

If you're willing to buy a printed book, you'll find lots of useful
material in The Rails Way (the best current book for anyone who wants
to dive deeper into Rails), There's also an entire book devoted to
Active Record (Pro Active Record), which has lots of detail but also
some inaccuracies (see http://blog.hasmanythrough.com/2007/10/29/book-review-pro-active-record).
I suspect it will be a much better book in its second edition. You can
purchase that book as an ebook from the book's web site (http://
apress.com/book/view/1590598474).

Michael Slater
www.BuildingWebApps.com
Resources for Rails Developers