About to migrate :string but I'm thinking :text might be better. Performance/Purpose?

Question

class CreateScrapes < ActiveRecord::Migration
  def self.up
    create_table :scrapes do |t|
      t.text :saved_characters
      t.text :sanitized_characters
      t.string :href

      t.timestamps
   end
  end

  def self.down
    drop_table :scrapes
  end
end

I'm about to rake db:migrate and I'm think about the attribute type if I should be using text or string. Since saved_characters and sanitized_characters will be arrays with thousands of unicode values, its basically comma delimited data, I'm not sure if `:text' is really the right way to go here. What would you do?

Answer 1

Assuming you're on MySQL, the real difference between :string and :text is length. Rails uses the varchar column type for :string columns, and sets a 255 character limit on :string columns. :text, usuprisingly, uses the text column.

To me, this suggests that :string would be a really bad choice for your columns, as they are likely to exceed 255 characters.

Answer 2

:string is only 255 characters. you probably want :text since you mention thousands.