Why Does EF Core's `Update-Database` Fail Due to Existing Database Objects, and How Can I Fix It?

EF Core's Update-Database Fails Due to Existing Object in the Database

In ASP.Net Core using Entity Framework Core, attempting to update the database may fail with an error indicating that an object with the same name already exists in the database. This error arises if manual updates were made to the database after using the command line to update it.

The commonly suggested solution is to employ the "Add-migration 'Reset' -IgnoreChanges" command, as outlined by John Salewski. However, this approach may fail due to the absence of the -IgnoreChanges parameter in EF Core.

Resolution:

To resolve this issue, follow these steps:

1. Comment Out Up() Method:

   • Find the migration file associated with the manual database changes.
   • Comment out all the code in the Up() method of this migration file.

2. Apply the Migration:

   • Run the following command:

     Add-Migration Initialization
     Update-Database

     Copy after login

This procedure creates a snapshot of the current database state. Future migrations will only include changes made after this baseline.

3. Add Changes Back:

   • If necessary, revert any manual database changes and create a new migration file to incorporate the incremental model changes.
   • Add a second migration to the database.

By commenting out the Up() method, EF Core retains the current database schema and avoids conflicts with existing objects. Once the baseline migration is applied, subsequent migrations can safely introduce new changes, ensuring a seamless update process.

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