How to unapply a migration in ASP NET Core with EF Core

Question

When I run PM gt  Remove-Migration -context BloggingContext in VS2015 with an ASP NET Core project using EF Core I get the following error   System InvalidOperationException  The migration  20160703192724 MyFirstMigration  has already been applied to the database  Unapply it and try again  If the migration has been applied to other databases  consider reverting its changes using a new migration     at Microsoft EntityFrameworkCore Migrations Design MigrationsScaffolder RemoveMigration String projectDir  String rootNamespace  Boolean force       at Microsoft EntityFrameworkCore Design MigrationsOperations RemoveMigration String contextType  Boolean force       at Microsoft EntityFrameworkCore Tools Cli MigrationsRemoveCommand  lt  gt c  DisplayClass0 0  lt Configure gt b  0        at Microsoft Extensions CommandLineUtils CommandLineApplication Execute String   args       at Microsoft EntityFrameworkCore Tools Cli Program Main String   args    The migration  20160703192724 MyFirstMigration  has already been applied to the database  Unapply it and try again  If the migration has been applied to other databases  consider reverting its changes using a new migration    How can I unapply it  I m using latest release of ASP NET Core 1 0  EF Core  and VS2015 Update 3

User · Answer

In order to unapply a migration in EF Core 1.0 use the command:

dotnet ef database update {migration_name}

Use the migration name of the migration until which you would like to preserve your changes. The list of names of the migration can be found using:

dotnet ef migrations list

User · Answer

1 find table  dbo  EFMigrationsHistory   then delete the migration record that you want to remove  2  run  remove-migration  in PM Package Manager Console   Works for me

User · Answer

You should delete migration  20160703192724 MyFirstMigration  record from    EFMigrationsHistory  table  otherwise this command will remove migration and delete migrations folder  PMC Command      gt  remove-migration -force  CLI Command      gt  dotnet ef migrations remove -f  Link About CLI Commands Link About PMC Commands

User · Answer

More details and solutions here  I don t understand why we are confusing things up here  So I ll write down a clear explanation  and what you have to notice  All the commands will be written using dotnet  This solution is provided for  net Core 3 1  but should be compatible with all other generations as well Removing migrations   Removing a migration deletes the file from your project  which should be clear for everyone  Removing a migration can only be done  if the migration is not applied to the database yet To remove last created migration  cd to your project then dotnet ef migrations remove  Note  Removing a migration works only  if you didn t execute yet dotnet ef database update or called in your c  code Database Migrate    in other words  only if the migration is not applied to your database yet  Unapplying migrations  revert migrations    Removes unwanted changes from the database Does not delete the migration file from your project  but allows you to remove it after unapplying To revert a migration  you can either   Create a new migration dotnet ef migrations add  lt your changes gt  and apply it  which is recommended by microsoft  Or  update your database to a specified migration  which is basically unapplying or reverting the non chosen migrations  with dotnet ef database update  lt your migration name to jump back to gt     Note  if the migration you want to unapply  does not contain a specific column or table  which are already in your database applied and being used  the column or table will be dropped  and your data will be lost  After reverting the migration  you can remove your unwanted migration Hopefully this helps someone

User · Answer

To unapply a specific migration s    dotnet ef database update LastGoodMigrationName or PM gt  Update-Database -Migration LastGoodMigrationName   To unapply all migrations   dotnet ef database update 0 or PM gt  Update-Database -Migration 0   To remove last migration   dotnet ef migrations remove or PM gt  Remove-Migration   To remove all migrations    just remove Migrations folder   To remove last few migrations  not all    There is no a command to remove a bunch of migrations and we can t just remove these few migrations and their   designer cs files since we need to keep the snapshot file in the consistent state   We need to remove migrations one by one  see To remove last migration above    To unapply and remove last migration   dotnet ef migrations remove --force or PM gt  Remove-Migration -Force

User · Answer

Use   CLI   gt  dotnet ef database update  lt previous-migration-name gt   Package Manager Console  PM gt  Update-Database  lt previous-migration-name gt   Example   PM gt  Update-Database MyInitialMigration  Then try to remove last migration    Removing migration without database update doesn t work because you applied changes to database   If using PMC  Try  PM  update-database 0 This will wipe the database and allow you to remove the Migration Snapshot on your Solution

User · Answer

You can do it with  dotnet ef migrations remove  Warning Take care not to remove any migrations which are already applied to production databases  Not doing so will prevent you from being able to revert it  and may break the assumptions made by subsequent migrations

User · Answer

To  unapply  the most  recent   migration after it has already been applied to the database    Open the SQL Server Object Explorer  View -   SQL Server Object Explorer   Navigate to the database that is linked to your project by expanding the small triangles to the side   Expand  Tables  Find the table named  dbo  EFMigrationsHistory   Right click on it and select  View Data  to see the table entries in Visual Studio   Delete the row corresponding to your migration that you want to unapply  Say  yes  to the warning  if prompted    Run  dotnet ef migrations remove  again in the command window in the directory that has the project json file  Alternatively  run  Remove-Migration  command in the package manager console    Hope this helps and is applicable to any migration in the project    I tested this out only to the most recent migration     Happy coding

User · Answer

Note  It might be troublesome later on  I used it as a last resort since non of the solutions provided above and others did not work in my case   Copy the code from the body of previous successful migration s down   method  Add a new migration using Add-Migration  quot migration-name quot  Paste the copied code from the down   method of previous migration to the new migration s Up   method  Up      paste here   Run Update-Database Done  your changes from the previous migration should now have been reverted

User · Answer

You can still use the Update-Database command   Update-Database -Migration  lt migration name gt  -Context  lt context name gt    However  judging by the name of your migration i m assuming it s the first migration so that command may not work   You should be able to delete the entry from the   MigrationHistory table in your database and then run the Remove-Migration command again   You could also delete the migration file and just start again

User · Answer

In general if you are using the Package Manager Console the right way to remove a specific Migration is by referencing the name of the migration  Update-Database -Migration  Name of Migration  -Context  context    Another way to remove the last migration you have applied according to the docs is by using the command   dotnet ef migrations remove   This command should be executed from the developer command prompt  how to open command prompt  inside your solution directory   For example if your application is inside name  Application  and is in the folder c  Projects  Then your path should be   C  Projects Application

User · Answer

in Package Manager Console  just Type Remove-Migration And Press Enter  It automatically removes the migration  Tools - gt  Nuget Package Manager - gt  Package Manager Console

User · Answer

To revert all the migrations which are applied to DB simply run   update-database 0   It should be followed with running Remove-Migration as many times as there are migration files visible in the Migration directory  The command deletes the latest migration and also updates the snapshot

User · Answer

In Package Manager Console    Update-Database Your Migration You Want To Revert To  More options and explanation on how to revert migrations can be seen here

User · Answer

To revert the last applied migration you should  package manager console commands     Revert migration from database  PM gt  Update-Database  lt prior-migration-name gt  Remove migration file from project  or it will be reapplied again on next step  Update model snapshot  PM gt  Remove-Migration   UPD  The second step seems to be not required in latest versions of Visual Studio  2017

User · Answer

at first run the following command    PM gt update-database -migration 0   and then run this one    PM gt remove migration   Finish

User · Answer

To completely remove all migrations and start all over again  do the following   dotnet ef database update 0 dotnet ef migrations remove

User · Answer

Simply you can target a Migration by value   Update-Database -Migration 0   Then go ahead and remove it   Remove-Migration

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