Uninitialized constant CreateDb when using rake db:migrate

Does anyone have any idea why I might be getting this error? I’m using
sqlite3 with Rails 1.2.3 and ruby 1.8.5 (2006-08-25) [i486-linux]

rake db:migrate --trace
(in /home/robhu/incremental)
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:migrate
rake aborted!

/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:266:in
load_missing_constant' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:452:inconst_missing’
/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/dependencies.rb:464:in
const_missing' /usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/inflector.rb:250:inconstantize’
/usr/lib/ruby/gems/1.8/gems/activesupport-1.4.2/lib/active_support/core_ext/string/inflections.rb:148:in
constantize' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:366:inmigration_class’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:346:in
migration_classes' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/connection_adapters/sqlite_adapter.rb:352:ininject’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:342:in
each' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:342:ininject’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:342:in
migration_classes' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:330:inmigrate’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:297:in
up' /usr/lib/ruby/gems/1.8/gems/activerecord-1.15.3/lib/active_record/migration.rb:288:inmigrate’
/usr/lib/ruby/gems/1.8/gems/rails-1.2.3/lib/tasks/databases.rake:4
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:392:in call' /usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:392:inexecute’
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:392:in each' /usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:392:inexecute’
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:362:in invoke' /usr/lib/ruby/1.8/thread.rb:135:insynchronize’
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:355:in invoke' /usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1739:intop_level’
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1739:in each' /usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1739:intop_level’
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1761:in
standard_exception_handling' /usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1733:intop_level’
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1711:in run' /usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1761:instandard_exception_handling’
/usr/lib/ruby/gems/1.8/gems/rake-0.7.3/lib/rake.rb:1708:in run' /usr/lib/ruby/gems/1.8/gems/rake-0.7.3/bin/rake:7 /usr/bin/rake:16:inload’
/usr/bin/rake:16

trueman% cat db/migrate/001_create_db.rb
class CreateTasks < ActiveRecord::Migration
def self.up
create_table :tasks do |t|
t.column :name, :string
end
end

def self.down
drop_table :tasks
end
end

-Rob


http://www.robhulme.com/
http://robhu.livejournal.com/

Think of how many religions attempt to validate themselves with
prophecy. Think of how many people rely on these prophecies, however
vague, however unfulfilled, to support or prop up their beliefs. Yet
has there ever been a religion with the prophetic accuracy and
reliability of science? … No other human institution comes close.
– Carl Sagan

Does anyone have any idea why I might be getting this error? I’m using
sqlite3 with Rails 1.2.3 and ruby 1.8.5 (2006-08-25) [i486-linux]
Aha. The reason was something to do with creating
db/migrate/001_foo.rb myself. When I used the generator it worked
fine.

-Rob


http://www.robhulme.com/
http://robhu.livejournal.com/

Saying that Java is good because it works on all platforms is like
saying anal sex is good because it works on all genders.
–Anonymous

On 9/11/07, Robert H. [email protected] wrote:

Does anyone have any idea why I might be getting this error? I’m using
sqlite3 with Rails 1.2.3 and ruby 1.8.5 (2006-08-25) [i486-linux]

trueman% cat db/migrate/001_create_db.rb
class CreateTasks < ActiveRecord::Migration

The migration code looks for a class based on the file name of the
migration. So since your migration file is named 001_create_db.rb, it
strips off the 001_ part and turns create_db into the class CreateDb
and tries to peform CreateDb.up, which can’t be found.

So you need to either name the migration file as 001_create_tasks.rb,
or rename the class to CreateDb.

You found out that the generator keeps things in order for you. If you
need a migration to add a table, I suggest you generate a model
instead of a migration. The model generator will create a migration
for you as it creates the model skeleton.

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