EF CORE创建组合主键

使用modelBuilder.Entity<Type>().HasKey指定多个字段即可

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Course>().ToTable("Course");
    modelBuilder.Entity<Enrollment>().ToTable("Enrollment");
    modelBuilder.Entity<Student>().ToTable("Student");
    modelBuilder.Entity<Department>().ToTable("Department");
    modelBuilder.Entity<Instructor>().ToTable("Instructor");
    modelBuilder.Entity<OfficeAssignment>().ToTable("OfficeAssignment");
    modelBuilder.Entity<CourseAssignment>().ToTable("CourseAssignment");

    //组合主键
    modelBuilder.Entity<CourseAssignment>()
        .HasKey(c => new { c.CourseID, c.InstructorID });
}