I understand you will find many database design tool, database modeling tool. Example, ER-win , db desginer and etc.

But, they aren't supported for Ruby on Rails.

What's the easiest way or tool to create database for Ruby on Rails?

Appended:

I understand the rails development phases are growing step-by-step. But, When beginning of project, I believe database modeling needs to be first. Which database modeling tool can one use?

With Rails, you do not. You design the item model, the database model is produced. All database handling is completed in the model.

With Rails you utilize migrations to create your database. Give migrations a go - I figured I'd miss the diagrams in SQL Server after i began dealing with Rails however i don't.

You can observe your schema in an exceedingly readable text form at db/schema.rb

You are working in internet marketing backwards. Don't determine the table structure you'll need, build the application around it. The Rails Strategy is to begin building your application's functionality, slowly, and add migrations to develop your database since you need it.

You'll finish track of a less complicated data model, nothing you do not need, as well as your data structure will reflect the interactions individuals have together with your site rather than the other way round.

You are able to certainly use individuals tools to produce your database, but without getting knowledge about how rails handles associations you might encounter trouble. Not too you cannot deal with the default way rails does things, but you'll turn it into a lot harder on yourself.

So design your database, but know rails associations.

Like others have stated, you need to give migrations a go. The Rails Getting Began guides are very useful in explaining the salt water evaporates.

http://guides.rails.info/getting%5Fstarted.html

That one is particularly about migrations: http://guides.rails.info/migrations.html

Trying carrying out a fundamental migration, and you will see it's increasingly simple. If you want to make changes or change your migration, then take a look at that second link that covers more detail about migrations.

The Rails documentation can also be pretty useful for migrations: http://api.rubyonrails.org/classes/ActiveRecord/Migration.html

I understand documentation on this stuff can often be terrible, however in this situation it's worth looking.