Agile Web Development with Rails 7

Managing Tables

So far we’ve been using migrations to manipulate the columns in existing tables. Now let’s look at creating and dropping tables:

class CreateOrderHistories < ActiveRecord::Migration
  def change
    create_table :order_histories do |t|
      t.integer :order_id, null: false
      t.text :notes

      t.timestamps
    end
  end
end

create_table takes the name of a table (remember, table names are plural) and a block. (It also takes some optional parameters that we’ll look at in a minute.) The block is passed a table definition object, which we use to define the columns in the table.

Generally the call to drop_table isn’t needed, as create_table is reversible. drop_table accepts a single parameter, which is ...