How and Why To Avoid Nil in Rails

for hashes use

Hash.fetch(key)

active record

• find works just fine

• for dynamic finders, use bang methods

  Person.find_by_name!(name)

summary

• use your language and librearies intellingently
• invert the object relationshships
• guard against nil with a custom attribute reader
• introduce new domain concepts (like suscriber0)