What does "Build Failed" mean in relation to adding a migration in EF Core?

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"Build Failed" means that the process of compiling the code to create the migration file failed. It usually indicates that there is an error in the code, such as a syntax error or a missing reference. In EF Core, adding a migration requires creating a migration class and updating the database schema with the changes defined in the migration. When the code for the migration fails to compile, the build process fails and the migration cannot be added to the application.