How to reset a single table in rails?

Question

I want the primary key values to start from 1 again.

Answer 1

I don't think that you can do that. However you could write your own rake task

For your information, you can get the list of rake tasks available by doing:

rake --tasks

You'll get something like:

rake backups:clear             # Cleanup Backup files
rake clear                     # Cleanup temporary, log and backup files
rake db:fixtures:load          # Load fixtures into the current environment's database.  Load specific fixtures using FIXTURES=x,y
rake db:migrate                # Migrate the database through scripts in db/migrate. Target specific version with VERSION=x
rake db:schema:dump            # Create a db/schema.rb file that can be portably used against any DB supported by AR
rake db:schema:load            # Load a schema.rb file into the database
rake db:sessions:clear         # Clear the sessions table
rake db:sessions:create        # Creates a sessions table for use with CGI::Session::ActiveRecordStore
rake db:structure:dump         # Dump the database structure to a SQL file
rake db:test:clone             # Recreate the test database from the current environment's database schema
rake db:test:clone_structure   # Recreate the test databases from the development structure
rake db:test:prepare           # Prepare the test database and load the schema
rake db:test:purge             # Empty the test database
rake doc:app                   # Build the app HTML Files
rake doc:clobber_app           # Remove rdoc products
rake doc:clobber_plugins       # Remove plugin documentation
rake doc:clobber_rails         # Remove rdoc products
rake doc:plugins               # Generate documation for all installed plugins
rake doc:rails                 # Build the rails HTML Files
rake doc:reapp                 # Force a rebuild of the RDOC files
rake doc:rerails               # Force a rebuild of the RDOC files
rake log:clear                 # Truncates all *.log files in log/ to zero bytes
rake rails:freeze:edge         # Lock to latest Edge Rails or a specific revision with REVISION=X (ex: REVISION=4021) or a tag with TAG=Y (ex: TAG=rel_1-1-0)
rake rails:freeze:gems         # Lock this application to the current gems (by unpacking them into vendor/rails)
rake rails:unfreeze            # Unlock this application from freeze of gems or edge and return to a fluid use of system gems
rake rails:update              # Update both configs, scripts and public/javascripts from Rails
rake rails:update:configs      # Update config/boot.rb from your current rails install
rake rails:update:javascripts  # Update your javascripts from your current rails install
rake rails:update:scripts      # Add new scripts to the application script/ directory
rake stats                     # Report code statistics (KLOCs, etc) from the application
rake test                      # Test all units and functionals
rake test:functionals          # Run the functional tests in test/functional
rake test:integration          # Run the integration tests in test/integration
rake test:plugins              # Run the plugin tests in vendor/plugins/**/test (or specify with PLUGIN=name)
rake test:recent               # Test recent changes
rake test:uncommitted          # Test changes since last checkin (only Subversion)
rake test:units                # Run the unit tests in test/unit
rake tmp:assets:clear          # Clears all files in tmp/test/assets
rake tmp:cache:clear           # Clears all files and directories in tmp/cache
rake tmp:clear                 # Clear session, cache, and socket files from tmp/
rake tmp:create                # Creates tmp directories for sessions, cache, and sockets
rake tmp:pids:clear            # Clears all files in tmp/pids
rake tmp:sessions:clear        # Clears all files in tmp/sessions
rake tmp:sockets:clear         # Clears all files in tmp/sockets

via

Answer 2

Have a look here, you still might need a little customization to truncate a specific table.