以下关系创建外键Map

@Entity
public class Department {
   @Id
   private String name;

   //some more fields
}

@Entity
public class Employee {
   @Id
   private long id;

   private String name;
   private String designation;

   @ManyToOne
   @JoinColumn(name = "fk_department_id", foreignKey = @ForeignKey(name="fk_department"))
   private Department department;
}

生成：
…约束 fk_department 外键( fk_department_id )参考文献 department ( name )
问题：如何在hibernate中触发这个约束的创建，而不必创建 Department 实体？
例如只是添加外键 @Id 没有显式实体引用的字段。但在初始创建时仍会触发fk。以下内容当然无效：

@ManyToOne
   @JoinColumn(name = "fk_department_id", foreignKey = @ForeignKey(name="fk_department"))
   private String department;

你明白我的意图了。有可能吗？
（旁注：我对通过启动ddl/sql语句创建外键链接不感兴趣）。