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 class="native"/>     </id>     <property name="fieldName"/>     <property name="fieldLabel"></property>     <many-to-one name="fieldType"></many-to-one>     <many-to-one name="fieldInput"></many-to-one>     <many-to-one name="flowForm"></many-to-one>     <list table="T_FieldItem" name="items">        <key column="formfieldId"></key>        <list-index column="itemIndex"></list-index>        <composite-element class="com.nqyw.oa.model.FieldItem">           <property name="label"></property>           <property name="value"></property>        </composite-element>     </list>   </class> </hibernate-mapping>

2.

 

<?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_FlowForm" name="com.nqyw.oa.model.FlowForm">     <id name="id">       <generator class="native"/>     </id>     <property name="template"/>     <set inverse="true" cascade="save-update"  name="fields">         <key column="flowformId"></key>         <one-to-many class="com.nqyw.oa.model.FormField"/>     </set>   </class> </hibernate-mapping>

 

如果有：cascade="save-update" 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。

 

 

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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。