cascade="save-update" 与 inverse="true"运用讲解（回钦波）

cascade="save-update" 与 inverse="true"使用讲解（回钦波）

今天在hibernate-hbm.xml里面做了调试发现casecade 和 inverse 的用法所在：

?

?

1.

?

public class FlowForm {
?private int id;
?private String template;
?private Set fields;
?
?
?public Set getFields() {
??return fields;
?}
?public void setFields(Set fields) {
??this.fields = fields;
?}
?public int getId() {
??return id;
?}
?public void setId(int id) {
??this.id = id;
?}
?public String getTemplate() {
??return template;
?}
?public void setTemplate(String template) {
??this.template = template;
?}
?

?

?

public class FormField {
?private int id;
?/**
? * 表单域类型
? */
?private FieldType fieldType;
?/**
? *表单输域入类型
? */
?private FieldInput fieldInput;
?/**
? * 表单域名称
? */
?private String fieldName;
?/**
? * 表单域标签
? */
?private String fieldLabel;
?/**
? * 表单
? * @return
? */
?private FlowForm flowForm;
?/**
? * 表单域items
? * @return
? */
?private List<FieldItem> items;
?
?
?public List<FieldItem> getItems() {
??return items;
?}
?public void setItems(List<FieldItem> items) {
??this.items = items;
?}
?public FieldInput getFieldInput() {
??return fieldInput;
?}
?public void setFieldInput(FieldInput fieldInput) {
??this.fieldInput = fieldInput;
?}
?public FlowForm getFlowForm() {
??return flowForm;
?}
?public void setFlowForm(FlowForm flowForm) {
??this.flowForm = flowForm;
?}
?public String getFieldLabel() {
??return fieldLabel;
?}
?public void setFieldLabel(String fieldLabel) {
??this.fieldLabel = fieldLabel;
?}
?public String getFieldName() {
??return fieldName;
?}
?public void setFieldName(String fieldName) {
??this.fieldName = fieldName;
?}
?public FieldType getFieldType() {
??return fieldType;
?}
?public void setFieldType(FieldType fieldType) {
??this.fieldType = fieldType;
?}
?public int getId() {
??return id;
?}
?public void setId(int id) {
??this.id = id;
?}

?

?测试：

?

Session session = null;
??session =HibernateUtils.getSession();
??session.beginTransaction();
??FlowForm flowForm = new FlowForm();
??flowForm.setTemplate("楼中阁");
??
?
??FormField field1 = new FormField();
??field1.setFieldLabel("姓名:回钦波");
??field1.setFieldName("name");
??
??
??FormField field2 = new FormField();
??field2.setFieldLabel("姓名2：:回钦波");
??field2.setFieldName("name2");
??
??
??FormField field3 = new FormField();
??field3.setFieldLabel("姓名3：:回钦波");
??field3.setFieldName("name3");
??
??
??FormField field4 = new FormField();
??field4.setFieldLabel("姓名4：:回钦波");
??field4.setFieldName("name4");
??
??Set<FormField> set = new HashSet<FormField>();
??set.add(field1);
??set.add(field2);
??set.add(field3);
??set.add(field4);
??
??flowForm.setFields(set);
??session.save(flowForm);
??
??session.getTransaction().commit();
??
??if(session.getTransaction().isActive()){
???session.getTransaction().wasRolledBack();
??}
??HibernateUtils.closeSession(session);
??

?

配置文件：

1.

?

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
? <class table="T_FormField" name="com.nqyw.oa.model.FormField">
??? <id name="id">
????? <generator name="items">
?????? <key column="formfieldId"></key>
?????? <list-index column="itemIndex"></list-index>
?????? <composite-element encoding="ISO-8859-1"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
? <class table="T_FlowForm" name="com.nqyw.oa.model.FlowForm">
??? <id name="id">
????? <generator cascade="save-update"? name="fields">
??????? <key column="flowformId"></key>
??????? <one-to-many 和 inverse="true" ,表示我父（FlowForm.java)爸爸要负责维护子的关系，

SQL语句是：

Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)
Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)
Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)
Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)

如果没有cascade="save-update",的话，保存父（FlowForm.java)时 子类（FormField.java)是不能被保存的。

?

?

－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－

如果有 ：cascade="save-update"?而没有?inverse="true" ,表示我父（FlowForm.java)爸爸要负责维护子的关系，

SQL语句是：

Hibernate: insert into T_FlowForm (template) values (?)
Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)
Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)
Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)
Hibernate: insert into T_FormField (fieldName, fieldLabel, fieldType, fieldInput, flowForm) values (?, ?, ?, ?, ?)
Hibernate: update T_FormField set flowformId=? where id=?
Hibernate: update T_FormField set flowformId=? where id=?
Hibernate: update T_FormField set flowformId=? where id=?
Hibernate: update T_FormField set flowformId=? where id=?

多了四条是因为父类这边在添加完父子下，还要更新管理下子类。所以最好加上??inverse="true"。这样会提高效率

如果没有cascade="save-update",的话，保存父（FlowForm.java)时 子类（FormField.java)是不能被保存的。

查看更多 下一篇