Hibernate查询语言HQL学习。HQL特点介绍。HQL是面向对象的查询语句，它的功能非常强大，具备继承、多态、关联等特性 。除了Java类与属性的名称外，查询语句对大小写并不敏感。下面以班级与学生进行HQL示例，先建立Student.java、Classes.java以及映射文件，实例代码如下：
Student.java代码：
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public class Student { private int id; private String name; private Date createTime; private Classes classes; |
Classes.java代码：
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public class Classes { private int id; private String name; private Set students; |
Student.hbm.xml：映射文件
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<hibernate-mapping> <class name=”hibernate.Student” table=”t_student”> <id name=”id”> <generator class=”native”/> </id> <property name=”name”/> <property name=”createTime”/> <many-to-one name=”classes” column=”classesid”/> </class> </hibernate-mapping> |
Classes.hbm.xml：映射文件
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<hibernate-mapping package=”hibernate”> <class name=”Classes” table=”t_classes”> <id name=”id”> <generator class=”native”/> </id> <property name=”name”/> <set name=”students” inverse=”true” cascade=”all”> <key column=”classesid”/> <one-to-many class=”Student”/> </set> </class> </hibernate-mapping> |