What program is easy to created digram for database.. i dont have sql program

Here is your one stop shop for DB Modeling tools, the link provides an exhaustive list of software and their license model. Many are free. http://www.databaseanswers.org/modelling_tools.htm compliments of @fatherjack from a previous post, link is below.

I had asked a question about good ERD tools before. You can see my question and the great responses here

This is one mentioned in a Sybex book I have been reading (I have not used it any): Open System Architecture (OSA) http://www.codebydesign.com/. I did not see it mentioned on the link Tim provided but I just skimmed over the page. It is a little bit more manual task compared to using Visio, but it is free compared to Visio. It will run on Windows and Linux. The book I referenced this from: SQL Server 2008 Administration: Real World Skills for MCITP Certification and Beyond (ISBN:978-0-470-55420-3). On page 210 it shows brief example of using it.

I heartily suggest you go on over to Atlantis Interactive and check out the amazing tool set that @Matt Whitfield has now released for free.

You will be wanting Schema Surf, which can export a diagram for you.