Hibernate常用注释收集7

映射本地化查询

通过@SqlResultSetMapping 注解来描述 SQL 的 resultset 结构。如果定义多个结果集映射，
则用 @SqlResultSetMappings。

@NamedNativeQuery(name=”night&area”, query=”select night.id nid, night.night_duration, “
+ ” night.night_date, area.id aid, night.area_id, area.name “
+ “from Night night, Area area where night.area_id = area.id”,
resultSetMapping=”joinMapping”)

@SqlResultSetMapping( name=”joinMapping”, entities={
@EntityResult(entityClass=org.hibernate.test.annotations.query.Night.class, fields = {
@FieldResult(name=”id”, column=”nid”),
@FieldResult(name=”duration”, column=”night_duration”),
@FieldResult(name=”date”, column=”night_date”),
@FieldResult(name=”area”, column=”area_id”),
discriminatorColumn=”disc”
}),

@EntityResult(entityClass=org.hibernate.test.annotations.query.Area.class, fields = {
@FieldResult(name=”id”, column=”aid”),
@FieldResult(name=”name”, column=”name”)
})
}
)

上面的例子，名为”night&area”的查询和 “joinMapping”结果集映射对应，该映射返回两个
实体，分别为 Night 和 Area, 其中每个属性都和一个列关联，列名通过查询获取。

@Entity
@SqlResultSetMapping(name=”implicit”,
entities=@EntityResult(
entityClass=org.hibernate.test.annotations.@NamedNativeQuery(
name=”implicitSample”, query=”select * from SpaceShip”,
resultSetMapping=”implicit”)
public class SpaceShip {
private String name;
private String model;
private double speed;
@Id
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Column(name=”model_txt”)
public String getModel() {
return model;
}
public void setModel(String model) {
this.model = model;
}
public double getSpeed() {
return speed;
}
public void setSpeed(double speed) {
this.speed = speed;
}
}

上例中 model1 属性绑定到 model_txt 列，如果和相关实体关联设计到组合主键，那么应
该使用 @FieldResult 注解来定义每个外键列。@FieldResult的名字组成：定义这种关系的
属性名字 + “.” + 主键名或主键列或主键属性。

@Entity
@SqlResultSetMapping(name=”compositekey”,
entities=@EntityResult(entityClass=org.hibernate.test.annotations.query.SpaceShip.class,
fields = {
@FieldResult(name=”name”, column = “name”),
@FieldResult(name=”model”, column = “model”),
@FieldResult(name=”speed”, column = “speed”),
@FieldResult(name=”captain.firstname”, column = “firstn”),
@FieldResult(name=”captain.lastname”, column = “lastn”),
@FieldResult(name=”dimensions.length”, column = “length”),
@FieldResult(name=”dimensions.width”, column = “width”)
}),
columns = { @ColumnResult(name = “surface”),

@ColumnResult(name = “volume”) } )
@NamedNativeQuery(name=”compositekey”,
query=”select name, model, speed, lname as lastn, fname as firstn, length, width, length * width
as resultSetMapping=”compositekey”)
})

如果查询返回的是单个实体，或者打算用系统默认的映射，这种情况下可以不使用
resultSetMapping，而使用resultClass属性，例如：

@NamedNativeQuery(name=”implicitSample”, query=”select * from SpaceShip”,
resultClass=SpaceShip.class)
public class SpaceShip {

声明: 除非转自他站（如有侵权，请联系处理）外，本文采用 BY-NC-SA 协议进行授权 | 嗅谱网
转载请注明：转自《Hibernate常用注释收集7》
本文地址：http://www.xiupu.net/archives-278.html
关注公众号：