How to Revert an Applied EF Core Migration

A migration is applied, and you need it undone: it was a mistake, or you want to test it again from the start. EF Core reverts migrations with the same command that applies them, dotnet ef database update, pointed at an earlier migration. This guide reverts one migration, then all of them, and shows the two things to check before you do it on a database you care about: whether Down can undo the data, and what it deletes.

How Reverting Works

Every migration has two methods: Up, which applies the change, and Down, which undoes it. EF Core's tools reference explains the target argument: "The migration argument specifies the state the database should be in after the command completes. If the database is currently at a newer migration, the command reverts every migration newer than the target by executing its Down operations."

So you don't name the migration to undo; you name the one to go back to.

Prerequisites

• A .NET C# project with applied EF Core migrations. The examples use EF Core 10 with Oracle's MySql.EntityFrameworkCore and MySQL 9.7, with the DbContext in a class library.
• dotnet ef: How to Install dotnet-ef as a Local Tool in a .NET C# Project.

Step 1: Revert the Last Migration

The last applied migration was MakeDescriptionRequired, and the one before it RestrictCategoryDelete. Update the database to the earlier one:

Terminal

dotnet ef database update RestrictCategoryDelete --project src/Dewiride.Inventory.Data --startup-project src/Dewiride.Inventory.Api

Output (the lines that matter)

Reverting migration '20261103044430_MakeDescriptionRequired'.
      ALTER TABLE `products` MODIFY `Description` longtext NULL;
      DELETE FROM `__EFMigrationsHistory`
      WHERE `MigrationId` = '20261103044430_MakeDescriptionRequired';
Done.

Two things happened: Down ran, making the column nullable again, and the migration's row left the history table. The migration still exists in the code, now pending:

Output (dotnet ef migrations list, last lines)

20261103044319_RestrictCategoryDelete
20261103044430_MakeDescriptionRequired (Pending)

From here you can apply it again with dotnet ef database update, or remove it from the code with dotnet ef migrations remove; How to Remove the Last EF Core Migration covers that.

Step 2: Check What Down Does to the Data

Down undoes the schema. It doesn't always undo the data, and it doesn't always succeed:

• It can fail. A migration that turned an enum column from numbers into names had a generated Down that changed the column straight back to int, and reverting failed with Incorrect integer value: 'Adjustment' for column 'Type' at row 3. I had to write the reverse data conversion into Down first; that fix has its own post.
• It doesn't restore old values. The revert in Step 1 made Description nullable again, but the rows that the migration had filled with '' stayed ''. They don't go back to NULL.
• It can delete data. A migration that created a table has a Down that drops it, with everything in it.

Read the Down method before reverting on any database with data worth keeping.

Step 3: Revert Everything

0 is a special target. The reference: "The number 0 is a special case that means before the first migration and causes all migrations to be reverted." On a development database:

Terminal

dotnet ef database update 0 --project src/Dewiride.Inventory.Data --startup-project src/Dewiride.Inventory.Api

Output (the lines that matter)

Reverting migration '20261103045135_AddMovementHistoryIndex'.
Reverting migration '20261103044948_StoreMovementTypeAsString'.
Reverting migration '20261103044922_AddStockMovements'.
      DROP TABLE `stock_movements`;
Reverting migration '20261103044319_RestrictCategoryDelete'.
Reverting migration '20261103044219_AddProductCheckConstraints'.
Reverting migration '20261103044154_SetUnitPricePrecision'.
Reverting migration '20261103044122_AddUniqueIndexes'.
Reverting migration '20261103043648_SetMaxLengths'.
Reverting migration '20261103043533_LowercaseTableNames'.
Reverting migration '20261103043401_CreateCatalogTables'.
      DROP TABLE `Products`;
      DROP TABLE `Categories`;
Done.

Newest first, every Down ran, and the tables were dropped. One table stays:

Output (SHOW TABLES)

+-----------------------+
| Tables_in_inventory   |
+-----------------------+
| __EFMigrationsHistory |
+-----------------------+
1 row in set (0.001 sec)

The history table itself survives, empty. Running dotnet ef database update afterwards applied all ten migrations again, which is also a good test that every Up and Down works.

Reverting deletes data

database update 0 dropped every table the migrations created, with all their rows. Use it only on a development database you can rebuild. On any other database, write a new migration instead of reverting.

Common Mistakes

Mistake	What happens	Do this instead
Naming the migration you want to undo	That one stays applied; only newer ones revert	Name the migration before it
Reverting without reading Down	Data loss, or a failure halfway	Read Down first
Reverting a shared or production database	Other systems lose data or columns they use	Add a new migration that undoes the change
Expecting Down to restore old values	Converted or filled values stay as they are	Write the reverse conversion into Down

Troubleshooting

Symptom	Likely cause	Fix
Incorrect integer value or similar while reverting	Down changes a type the current data can't fit	Convert the data in Down, before the AlterColumn
Cannot drop index … needed in a foreign key constraint	Down drops an index before creating its replacement	Reorder Down
The revert stops halfway	MySQL commits each schema change, so earlier statements stay	Check the tables, fix Down, and run the command again

FAQ

Is there a way to revert with a SQL script instead?

Yes: dotnet ef migrations script <newer> <older> generates a rollback script, which you can review and run yourself. How to Generate a SQL Script from EF Core Migrations shows one.

Does reverting need the migration's code?

Yes. Down lives in the migration file, so the code must still contain the migration. Revert before removing, never the other way round.

Conclusion

dotnet ef database update <migration> takes the database back to that migration by running every newer migration's Down method and deleting its history row; 0 reverts everything. Read Down before you run it: it can fail on data it didn't plan for, it doesn't restore converted values, and it drops whatever its Up created.

Additional Resources

• EF Core tools reference: dotnet ef database update
• Applying Migrations — command-line tools and SQL scripts.

Related

• How to Remove the Last EF Core Migration
• Fixed: "Incorrect integer value: 'Adjustment' for column 'Type' at row 3" When Reverting an EF Core Migration on MySQL
• How to List EF Core Migrations and See Which Ones Are Applied