I am new to Ruby on Rails

I have Problem while migrating Db

Can someone Plz explain

There are lot in migration. I have given the sample for db migration.

ActiveRecordMigration allows you to use Ruby to define changes to your database schema, making it possible to use a version control system to keep things synchronised with the actual code.

This has many uses, including:

• Teams of developers – if one person makes a schema change, the other developers just need to update, and run “rake migrate”.
• Production servers – run “rake migrate” when you roll out a new release to bring the database up to date as well.
• Multiple machines – if you develop on both a desktop and a laptop, or in more than one location, migrations can help you keep them all synchronised.

Create the migration
Run the generator:
ruby script/generate migration add_a_new_table

This will create the file db/migrate/001_add_a_new_table.rb

Edit the code to tell it what to do.
The method self.up is used when migrating to a new version, self.down is used to roll back any changes if needed. The class name needs to be the same as the migration name (i.e. db/migrate/001_add_a_new_table needs a class name of AddANewTable).

The ID column will be created automatically, so don’t do it here as well.

class AddANewTable < ActiveRecord::Migration
def self.up
create_table :users do |table|
table.column :name, :string
table.column :login, :string, :null => false
# This column will contain an MD5 hash.
table.column : password, :string, :limit => 32, :null => false
table.column :email, :string
end
end

def self.down
drop_table :users
end
end
Valid column types are integer, float, datetime, date, timestamp, time, text, string, binary, and boolean.

You can also populate or modify data in a migration. A common usage would be to populate the values in a lookup table:

def self.up
create_table :statuses do |t|
t.column :name, :string
end

Status.create :name=>"Complete"
Status.create :name=>"Incomplete"

end

Run the migration
rake db:migrate

Hope the above steps will help you to solve the problem. Or give me the detailed explanation about your problem which you have faced in migration.

thanks

__________________
Karpagarajan. R
Necessity is the mother of invention

Thanks for ur reply...

I have done the migration with some samples..like urs..