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With all of this in mind, we are finally ready to start coding our migrations! Throughout
the rest of this chapter, we??™ll walk you through the various CRUD operations as they relate to
migrations, and where possible, we??™ll compare and contrast the migration approach to that of
the traditional database development approach.
Creating Tables
The first thing you??™re going to want to do when you start using migrations is create the tables
that you??™re going to be using for your application.
Since this is our first migration and we want to move forward with our development
process, we??™ll be using the up method. And since we want to create our first table, we??™ll be
using the create_table method to give the table its definition. In the following code we create
a cows table:
# Script to create the first version of a cows table
def self.up
create_table :cows do |t|
t.column :name, :string
t.column :breed, :string
t.column :born_on, :datetime
t.column :milkable, :boolean
end
end
Before the code is run, your application database should be empty.


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