---
title: i did not know that
teaser:
tags: web,rails
author: Jared Carroll
published_on: 2007-09-21
---

Here's something I discovered the other day:

> ActiveRecord infers model attributes from the database. **Each attribute
> gets a getter, setter, and query method**.

A query method?  I know this is true for boolean columns but non boolean columns?

```ruby
class User < ActiveRecord::Base
end

users (id, name) # schema

def test_should_say_if_it_does_or_does_not_have_a_name_when_sent_name?
  user = User.new
  assert ! user.name?

  user.name = ''
  assert ! user.name?

  user.name = 'name'
  assert user.name?
end
```

You get that query method for free for each of your `ActiveRecord` attributes.
From this passing test it looks as if for strings its implemented in terms of
String#blank?

This is nice because it can save you an extra message.

```ruby
if user.name.blank?
end
```

becomes

```ruby
if ! user.name?
end
```