在ssm中表的字段是本表的外键,这该如何进行关联修改

Question

因为在作一个小项目用的ssm,数据库用的mybatis,需要有子部门,在部门表中把部门表的一个字段作为本表的外键,需要对部门进行关联修改,但因为有外建修改或删除会有问题,如何解决import java.util.Set;public class Department {     @Override    public String toString() {        return "Department [d_id=" + d_id + ", d_name=" + d_name + ", d_description=" + d_description + ", u_parent="                + u_parent + ", sDepartments=" + sDepartments + "]";    }     private int d_id;     private String d_name;     private String d_description;     private Department u_parent;      public Department getU_parent() {        return u_parent;    }    public void setU_parent(Department u_parent) {        this.u_parent = u_parent;    }    private Set<Department> sDepartments;    public int getD_id() {        return d_id;    }    public void setD_id(int d_id) {        this.d_id = d_id;    }    public String getD_name() {        return d_name;    }    public void setD_name(String d_name) {        this.d_name = d_name;    }    public String getD_description() {        return d_description;    }    public void setD_description(String d_description) {        this.d_description = d_description;    }            public Set<Department> getsDepartments() {        return sDepartments;    }    public void setsDepartments(Set<Department> sDepartments) {        this.sDepartments = sDepartments;    }     }