Rails How can I rename a database column in a Ruby on Rails migration

Question

I wrongly named a column hased password instead of hashed password   How do I update the database schema  using migration to rename this column

User · Answer

I m on rails 5 2  and trying to rename a column on a devise User   the rename column bit worked for me  but the singular  table name threw a  User table not found  error   Plural worked for me   rails g RenameAgentinUser   Then change migration file to this   rename column  users   agent    agent   Where  agent  is the old column name

User · Answer

Just generate migration using command   rails g migration rename hased password   After that edit the migration add following line in change method  rename column  table   hased password   hashed password   This should do the trick

User · Answer

You have two ways to do this    In this type it automatically runs the reverse code of it  when rollback   def change   rename column  table name   old column name   new column name end  To this type  it runs the up method when rake db migrate and runs the down method when rake db rollback   def self up   rename column  table name   old column name   new column name end  def self down   rename column  table name  new column name  old column name end

User · Answer

def change     rename column  table name   old column name   new column name   end

User · Answer

Manually we can use the below method   We can edit the migration manually like    Open app db migrate xxxxxxxxx migration file rb Update hased password to hashed password Run the below command    gt  rake db migrate down VERSION xxxxxxxxx    Then it will remove your migration     gt  rake db migrate up VERSION xxxxxxxxx   It will add your migration with the updated change

User · Answer

As an alternative option  if you are not married to the idea of migrations  there is a compelling gem for ActiveRecord which will handle the name changes automatically for you  Datamapper style  All you do is change the column name in your model  and make sure you put Model auto upgrade  at the bottom of your model rb  and viola  Database is updated on the fly    https   github com DAddYE mini record  Note  You will need to nuke db schema rb to prevent conflicts  Still in beta phases and obviously not for everyone but still a compelling choice  I am currently using it in two non-trivial production apps with no issues

User · Answer

Run rails g migration ChangesNameInUsers  or whatever you would like to name it   Open the migration file that has just been generated  and add this line in the method  in between def change and end    rename column  table name   the name you want to change   the new name  Save the file  and run rake db migrate in the console  Check out your schema db in order to see if the name has actually changed in the database   Hope this helps

User · Answer

rename column  table   old column   new column   You ll probably want to create a separate migration to do this   Rename FixColumnName as you will     script generate migration FixColumnName   creates  db migrate xxxxxxxxxx fix column name rb   Then edit the migration to do your will     db migrate xxxxxxxxxx fix column name rb class FixColumnName  lt  ActiveRecord  Migration   def self up     rename column  table name   old column   new column   end    def self down       rename back if you need or do something else or do nothing   end end     For Rails 3 1 use   While  the up and down methods still apply  Rails 3 1 receives a change method that  knows how to migrate your database and reverse it when the migration is rolled back without the need to write a separate down method    See  Active Record Migrations  for more information   rails g migration FixColumnName  class FixColumnName  lt  ActiveRecord  Migration   def change     rename column  table name   old column   new column   end end   If you happen to have a whole bunch of columns to rename  or something that would have required repeating the table name over and over again   rename column  table name   old column1   new column1 rename column  table name   old column2   new column2       You could use change table to keep things a little neater   class FixColumnNames  lt  ActiveRecord  Migration   def change     change table  table name do  t        t rename  old column1   new column1       t rename  old column2   new column2               end   end end   Then just db migrate as usual or however you go about your business     For Rails 4   While creating a Migration for renaming a column  Rails 4 generates a change method instead of up and down as mentioned in the above section  The generated change method is       gt  rails g migration ChangeColumnName   which will create a migration file similar to   class ChangeColumnName  lt  ActiveRecord  Migration   def change     rename column  table name   old column   new column   end end

User · Answer

Run the below command to create a migration file   rails g migration ChangeHasedPasswordToHashedPassword   Then in the file generated in the db migrate folder  write rename column as below   class ChangeOldCoulmnToNewColumn  lt  ActiveRecord  Migration   def change      rename column  table name   hased password   hashed password   end end

User · Answer

Simply create a new migration  and in a block  use rename column as below   rename column  your table name   hased password   hashed password

User · Answer

If you need to switch column names you will need to create a placeholder to avoid a duplicate column name error  Here s an example   class SwitchColumns  lt  ActiveRecord  Migration   def change     rename column  column name   x   holder     rename column  column name   y   x     rename column  column name   holder   y   end end

User · Answer

For Ruby on Rails 4   def change     rename column  table name   column name old   column name new end

User · Answer

If your code is not shared with other one  then best option is to do just rake db rollback then edit your column name in migration and rake db migrate  Thats it  And you can write another migration to rename the column    def change     rename column  table name   old name   new name   end   Thats it

User · Answer

Rails 5 migration changes eg   rails g model Student student name string age integer  if you want to change student name column as name Note - if you not run rails db migrate You can do following steps  rails d model Student student name string age integer  This will remove generated migration file  Now you can correct your column name  rails g model Student name string age integer  If you migrated rails db migrate   following options to change column name  rails g migration RemoveStudentNameFromStudent student name string rails g migration AddNameToStudent name string

User · Answer

If the present data is not important for you  you can just take down your original migration using   rake db migrate down VERSION  YOUR MIGRATION FILE VERSION HERE    Without the quotes  then make changes in the original migration and run the up migration again by   rake db migrate

User · Answer

Generate a Ruby on Rails migration      gt  rails g migration Fixcolumnname   Insert code in the migration file  XXXXXfixcolumnname rb    class Fixcolumnname  lt  ActiveRecord  Migration   def change     rename column  table name   old column   new column   end end

User · Answer

If the column is already populated with data and live in production  I d recommend a step by step approach  so as to avoid downtime in production while waiting for the migrations   First I d create a db migration to add columns with the new name s  and populate them with the values from the old column name   class AddCorrectColumnNames  lt  ActiveRecord  Migration   def up     add column  table   correct name column one   string     add column  table   correct name column two   string      puts  Updating correctly named columns      execute  UPDATE table name SET correct name column one   old name column one  correct name column two   old name column two      end   end    def down     remove column  table   correct name column one     remove column  table   correct name column two   end end   Then I d commit just that change  and push the change into production   git commit -m  adding columns with correct name    Then once the commit has been pushed into production  I d run   Production   bundle exec rake db migrate   Then I d update all of the views controllers that referenced the old column name to the new column name   Run through my test suite  and commit just those changes   After making sure it was working locally and passing all tests first    git commit -m  using correct column name instead of old stinky bad column name    Then I d push that commit to production    At this point you can remove the original column without worrying about any sort of downtime associated with the migration itself   class RemoveBadColumnNames  lt  ActiveRecord  Migration   def up     remove column  table   old name column one     remove column  table   old name column two   end    def down     add column  table   old name column one   string     add column  table   old name column two   string   end end   Then push this latest migration to production and run bundle exec rake db migrate in the background   I realize this is a bit more involved of a process  but I d rather do this than have issues with my production migration

User · Answer

Update - A close cousin of create table is change table  used for changing existing tables  It is used in a similar fashion to create table but the object yielded to the block knows more tricks  For example   class ChangeBadColumnNames  lt  ActiveRecord  Migration   def change     change table  your table name do  t        t rename  old column name   new column name     end   end end   This way is more efficient if we do with other alter methods such as  remove add index remove index add column  eg we can do further like     Rename t rename  old column name   new column name   Add column t string  new column   Remove column t remove  removing column   Index column t index  indexing column

User · Answer

Some versions of Ruby on Rails support to up down method to migration and if you have up down method in your migration  then   def up     rename column  table name   column old name   column new name end  def down     rename column  table name   column new name   column old name end   If you have the change method in your migration  then   def change     rename column  table name   column old name   column new name end   For more information you can move  Ruby on Rails - Migrations or Active Record Migrations

User · Answer

From API   rename column table name  column name  new column name    It renames a column but keeps the type and content remains same

User · Answer

http   api rubyonrails org classes ActiveRecord Migration html  Under Available Transformations  rename column table name  column name  new column name    Renames a column but keeps the type and content

User · Answer

Let s KISS  All it takes is three simple steps  The following works for Rails 5 2   1   Create a Migration   rails g migration RenameNameToFullNameInStudents rails g RenameOldFieldToNewFieldInTableName - that way it is perfectly clear to maintainers of the code base later on   use a plural for the table name     2  Edit the migration    I prefer to explicitly write theupanddownmethods       db migrate 20190114045137 rename name to full name in students rb  class RenameNameToFullNameInStudents  lt  ActiveRecord  Migration 5 2    def up       rename column  table name   old column   new column     rename column  students   name   full name   end    def down               Note that the columns are reversed     rename column  students   full name   name   end end   3  Run your migrations  rake db migrate  And you are off to the races

User · Answer

I had this challenge when working on a Rails 6 application with PostgreSQL database  Here s how I fixed it  In my came the table name was Products  the old column was SKU and the new column was ProductNumber  Create a migration file that will contain the command for renaming the column  rails generate migration RenameSKUToProductNumberInProducts  Open the migration file in the db migrate directory  db migrate 20201028082344 rename sku to product number in products rb  Add the command for renaming the column  class RenameSkuToProductNumberInProducts  lt  ActiveRecord  Migration 6 0    def change       rename column  table name   old column   new column     rename column  products   sku   product number   end end  Save  and then run the migration command  rails db migrate  You can now confirm the renaming of the column by taking a look at the schema file  db schema rb  If you are not satisfied with the renaming of the column  you can always rollback  rails db rollback  Note  Endeavour to modify the column name to the new name in all the places where it is called  That s all  I hope this helps

User · Answer

Open your Ruby on Rails console and enter   ActiveRecord  Migration rename column  tablename   old column   new column

User · Answer

Generate the migration file   rails g migration FixName     Creates db migrate xxxxxxxxxx rb  Edit the migration to do your will   class FixName  lt  ActiveRecord  Migration   def change     rename column  table name   old column   new column   end end

User · Answer

In my opinion  in this case  it s better to use rake db rollback  then edit your migration and again run rake db migrate   However  if you have data in the column you don t want to lose  then use rename column

User · Answer

rails g migration RenameHashedPasswordColumn invoke  active record       create    db migrate 20160323054656 rename hashed password column rb   Open that migration file and  modify that file as below Do enter your original table name   class  RenameHashedPasswordColumn  lt  ActiveRecord  Migration   def change     rename column  table name   hased password   hashed password   end end

[ruby-on-rails] Rails: How can I rename a database column in a Ruby on Rails migration?

Examples related to ruby-on-rails

Examples related to ruby-on-rails-3

Examples related to migration

Examples related to rename

Examples related to alter-table