Don't understand migrations

rubyonrails-talk
1

If I use rake db:rollback it will delete a table I don't want. Then I add another migration with a new table. Then I run db:migrate. The table I didn't want is created again. How do I delete it so it doesn't come back?

2

Example :

class CreateNewTable< ActiveRecord::Migration   def self.up     create_table :new_tables do |t|       t.column :name, :string     end

  drop_table :old_tables

  #rename_table :old_tables, :new_tables   rename_table :books, :libraries

  #remove_column(table_name, column_name)   remove_column :items, :price

   #remove_column(table_name, column_name)    rename_column "users", "password", "hashed_password"

   #add_column table_names, new_column_names    add_column "users", "email"

  end

  def self.down     drop_table :lupa_passwords   end end

3

Visit Indonesia 2008 wrote:

Example :

class CreateNewTable< ActiveRecord::Migration   def self.up     create_table :new_tables do |t|       t.column :name, :string     end

  drop_table :old_tables

Thanks. Now I got it.

4

Pål Bergström wrote:

class CreateNewTable< ActiveRecord::Migration   def self.up     create_table :new_tables do |t|       t.column :name, :string     end

  drop_table :old_tables

Thanks. Now I got it.

Your customers won't mind copying all the data from the old table to the new one. (-: