How to set primary key in ruby on rails migration?

Question

How can I set primary key for my IdClient field? I have tried all methods, but I'll get errors (rails 3.0.9)... Could you help me?

class CreateCustomers < ActiveRecord::Migration
  def self.up
    create_table :customers do |t|
      t.integer :IdCustomer
      t.string :username
      t.string :crypted_password
      t.string :password_salt
      t.string :persistence_token
      t.string :email
      t.string :Skype
      t.string :ICQ
      t.string :Firstname
      t.string :Lastname
      t.string :Country
      t.string :State
      t.string :City
      t.string :Street
      t.string :Building
      t.integer :Room
      t.string :AddressNote
      t.date :DateOfReg
      t.integer :CustGroup
      t.float :TotalBuy

      t.timestamps
      add_index(:customers, :IdCustomer, :unique => true)
    end
  end

  def self.down
    drop_table :customers
  end
end

Also how to set relations in model?

Answer 1

Don't do this. Use the built-in id field as the primary key. If you're going to use Rails, you should build your app the "Rails way" unless you have very good reason not to.

If you really want to do this, you can pass a :primary_key option to create_table:

create_table :customers, :primary_key => :idClient do |t|
  # ...
end

You'll also need to tell your model the name of its primary key via self.primary_key = "idClient"