Regenerate DB

Rails
1

Hi again :),

I’m playing with migrations. I’ve created some migrations classes and
with
rake db:migrate the tables are created and altered fine, but then I
dropped
some of the tables and when I run db:migrate command again I don’t get
tables
being re-created.

What am I doing wrong? Is there a way to run db:migration in order to
drop the
tables?

2

On 7/13/06, Eduardo Yáñez Parareda [email protected] wrote:

What am I doing wrong? Is there a way to run db:migration in order to
drop the
tables?

–
Posted via http://www.ruby-forum.com/.

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Rails uses the schema_info table to determine what migrations to run.
When you drop a table via the command line, it doesn’t update the
schema_info table. The proper way is to run migrate with the version
option. For example if you had

class CreateUsers < ActiveRecord::Migration
def self.up
create_table :users do |t|
t.column :username, :string, :default => “”, :null => false
t.column :password_salt, :string
t.column :password_hash, :string
t.column :email, :string
end
end

def self.down
drop_table :users
end
end

And that was in 006_create_user.rb, then you would do
rake db:migrate VERSION=5

to migrate to the version below this one. It would call the down
method, which drops the users table.

Run rake db:migrate --help to see all the options.
Peak Obsession has a lot of
very useful information as well.

Pat

3

I would try:

rake db:migrate VERSION=1

then

rake db:migrate VERSION=X <- X is your last version

4

with
rake db:migrate the tables are created and altered fine, but then I
dropped
some of the tables and when I run db:migrate command again I don’t get
tables
being re-created.

What am I doing wrong? Is there a way to run db:migration in order to
drop the
tables?

I messed my tables up pretty good and found that rake migrate VERSION=0
dropped all tables in the database. Rake migrate then created new ones
to the latest level. Be very careful if you have data you would like to
preserve.

Regards,
Rich

5

Or add this to your Rakefile:

namespace :db do
desc “Revert database schema back to version 0, then up to the current
version.”
task :reload => :environment do
# migrate back to the stone age
ENV[‘VERSION’] = ‘0’
Rake::Task[“db:migrate”].execute

# forward, comrades, to the future!
ENV.delete('VERSION')
Rake::Task["db:migrate"].execute

# finally, load up the fixtures
Rake::Task["db:fixtures:load"].invoke

end
end

(snipped of technoweenie)