因為在作一個小項目用的ssm,數據庫用的mybatis,需要有子部門,在部門表中把部門表的一個字段作為本表的外鍵,需要對部門進行關聯修改,但因為有外建修改或刪除會有問題,如何解決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;?? ?}??? ?}