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Jaspreet kaur
Jaspreet kaur

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Undo a specific migration in Ruby!

In Ruby, usually if you want to alter the table which you created using the command Eg. "bundle exec rake db:create_migration NAME=create_games", and then "bundle exec rake db:migrate", you need to create a new migration, where you can add or change the columns.

But there is another way how you can alter the table without creating a new migration.

Check the migration status by running below in your terminal.

bundle exec rake db:migrate:status
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This will show you status of all migrations you created.
If the status is up, that means this migration is active: it's been run, and has updated the database successfully!

database: db/development.sqlite3

 Status   Migration ID    Migration Name
--------------------------------------------------
   up     20210719113216  Create games
   up     20210719113221  Create reviews
   up     20221110080300  Create users
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Now, for eg. if you want to change the games table , you need run the command below, where VERSION= 'Migration ID' from the status.

rake db:migrate:down VERSION=20210719113216
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database: db/development.sqlite3

 Status   Migration ID    Migration Name
--------------------------------------------------
  down    20210719113216  Create games
   up     20210719113221  Create reviews
   up     20221110080300  Create users
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This will change the status from active to inactive (down), plus it will remove the table from database and schema too,
Check your schema file, there is no games table -
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Now you can edit the table in the create_games migration, save and run-

bundle exec rake db:migrate
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This will create a new table with all the changes in the database and schema.

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