Question

I am trying to write a migration that will create a table and add a couple of indexes.

This is the migration:

class CreatePages < ActiveRecord::Migration
  def change
    create_table :pages do |t|
        t.string "name", :limit => 50
        t.string "permalink"
        t.integer "position"
        t.boolean "visible"
        t.integer "subject_id"

        add_index("pages","subject_id")
        add_index("pages","name")

      t.timestamps
    end
  end
end

When I trying and run this migration I get the following error:

PG::Error: ERROR: relation “pages” does not exist
: CREATE INDEX “index_pages_on_subject_id” ON “pages” (“subject_id”)

Can someone tell me what I’m doing wrong?

Thanks!

Answer 1

You need to call the add_index method outside your create_table block, or call index within the block.

The first method:

class CreatePages < ActiveRecord::Migration
  def change
    create_table :pages do |t|
        t.string "name", :limit => 50
        t.string "permalink"
        t.integer "position"
        t.boolean "visible"
        t.integer "subject_id"

      t.timestamps
    end

    add_index("pages","subject_id")
    add_index("pages","name")
  end
end

The second method:

class CreatePages < ActiveRecord::Migration
  def change
    create_table :pages do |t|
        t.string "name", :limit => 50
        t.string "permalink"
        t.integer "position"
        t.boolean "visible"
        t.integer "subject_id"
        t.index("subject_id")
        t.index("name")

      t.timestamps
    end


  end
end

Personally I’d go with the second as this is much neater.