dotnet ef migrations

Infrastructure\DependencyInjection\InfrastructureDependencyInjection.cs

services.AddDbContext<MySqlDatabase>(options =>
{
    options.UseSqlServer(ConnectionString);
});

Your target project 'BookApi' doesn't match your migrations assembly 'Infrastructure'.
Either change your target project or change your migrations assembly.

Change your migrations assembly by using DbContextOptionsBuilder.
E.g. options.UseSqlServer(connection, b => b.MigrationsAssembly("BookApi")).
By default, the migrations assembly is the assembly containing the DbContext.
Change your target project to the migrations project
by using the Package Manager Console's Default project drop-down list,
or by executing "dotnet ef" from the directory
containing the migrations project.

中英文对照，翻译上面的内容

services.AddDbContext<MySqlDatabase>(options =>
{
    options.UseSqlServer(ConnectionString, b => b.MigrationsAssembly("BookApi"));
});

目录结构

├─Application
├─BookApi
├─BookHandlerTest
├─Domain
└─Infrastructure

迁移命令

dotnet ef migrations add 'init' --project .\BookApi\
dotnet ef database update --project .\BookApi\