File: README — Documentation for db

DB Nazi

Encourages good DB practices in Active Record migrations.

What?

Active Record makes schema changes wonderfully easy, but due to some unfortunate defaults, it can be easy to forget to adhere to some basic database best practices, such as restricting columns to be non-nullable, or setting meaningful varchar limits. DB Nazi forces you to be explicit about these things so you can't simply forget.

It might take another 2 seconds to type null: true, but it may save you hours resolving integrity issues down the line!

Nullability

If DBNazi.require_nullability is set to true (the default), you must specify a :null option for all columns.

add_column :users, :awesome, :boolean              # raises DBNazi::NullabilityRequired
add_column :users, :awesome, :boolean, null: true  # ok

Varchar limits

If DBNazi.require_varchar_limits is set to true (the default), you must specify a :limit option for all :string columns.

add_column :users, :name, :string              # raises DBNazi::VarcharLimitRequired
add_column :users, :name, :string, limit: 100  # ok

Index uniqueness

If DBNazi.require_index_uniqueness is set the true (the default), you must specify a :unique option for all indexes.

add_index :users, :email                 # raises DBNazi::IndexUniquenessRequired
add_index :users, :email, unique: false  # ok

Usage

Since this tool is about enforcing developer discipline, I suggest including this only in the :development group in your Gemfile.

group :development do
  gem 'db_nazi'
end

If you have an established project, you probably don't want to lay the hard line on all your existing migrations. You can do this by specifying a minimum migration version in config/environments/development.rb:

DBNazi.from_version = 20120623000000

This means "only be a nazi from migration 20120623000000 onwards."

If you're using a migration written by a 3rd party, such as a generator you're using, I recommend editing it to conform to the rules above. After all, perhaps the 3rd party forgot a 'NOT NULL' or two.

If you're really sure you want to subvert DB Nazi for whatever reason, you may do so like this:

class BeAJerk < ActiveRecord::Migration
  no_nazi
  ...
end

Or just for a given block like this:

DBNazi.disable do
  ...
end

But no soup for you!

Contributing

Bug reports
Source
Patches: Fork on Github, send pull request.
- Include tests where practical.
- Leave the version alone, or bump it in a separate commit.