How to rollback just one step using rake db migrate

Question

After adding migration files in the db migrate folder and running rake db migrate  I want get back to the previous step  I think using VERSION n is the right way to do that  but I don t know the correct value of n to use  Is there any command to check the current n value   It would be great if anyone could provide full instructions on how to use rake db migrate

User · Accepted Answer

For starters  rake db rollback will get you back one step  then   rake db rollback STEP n  Will roll you back n migrations where n is the number of recent migrations you want to rollback    More references here

User · Answer

try            result DB  table  users  - gt whereExists function   Query                Query- gt where  id    lt    14162756                 Query- gt whereBetween  password   14162756 48384486                 Query- gt whereIn  id   3 8 12                     catch   Exception  error           Log  error  error           DB  rollBack 1           return redirect  - gt route  bye

User · Answer

Roll back the most recent migration   rake db rollback   Roll back the n most recent migrations   rake db rollback STEP n   You can find full instructions on the use of Rails migration tasks for rake on the Rails Guide for running migrations     Here s some more    rake db migrate - Run all migrations that haven t been run already rake db migrate VERSION 20080906120000 - Run all necessary migrations  up or down  to get to the given version rake db migrate RAILS ENV test - Run migrations in the given environment rake db migrate redo - Roll back one migration and run it again rake db migrate redo STEP n - Roll back the last n migrations and run them again rake db migrate up VERSION 20080906120000 - Run the up method for the given migration rake db migrate down VERSION 20080906120000 - Run the down method for the given migration     And to answer your question about where you get a migration s version number from      The version is the numerical prefix on the migration s filename  For   example  to migrate to version 20080906120000 run    rake db migrate VERSION 20080906120000     From Running Migrations in the Rails Guides

User · Answer

Other people have already answered you how to rollback  but you also asked how you could identify the version number of a migration    rake db migrate status gives a list of your migrations version  name and status  up or down  Your can also find the migration file  which contain a timestamp in the filename  that is the version number  Migrations are located in folder   db migrate

User · Answer

If the version is 20150616132425  then use   rails db migrate down VERSION 20150616132425

User · Answer

Best way is running Particular migration again by using down or up in rails 4  It s change      rails db migrate up VERSION timestamp   Now how you get the timestamp  Go to this path      db migrate   Identify migration file you want to revert pick the timestamp from that file name

[ruby-on-rails] How to rollback just one step using rake db:migrate

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