【发布时间】:2016-09-07 00:09:08
【问题描述】:
我想使用 kundera 作为框架并使用 cassandra 作为我的数据库,在我的传感器类与碎片类之间创建关系:
我想做的是:每个传感器都关联到很多部分:
传感器 1____0 * 个
但在进行此配置后(如下),我得到了两个没有任何关系的单独表:
idsensor | date | event_time | pressure | temperature
----------+-------+--------------------------+----------+-------------
1 | 33544 | 1970-01-01 00:00:00+0000 | 10 | 10
(1 rows)
cqlsh:sensor> select * from pieces;
idpiece | date | depth | event_time | height | idsensor | sensorkey | width
---------+------+-------+------------+--------+----------+-----------+-------
1 | null | 12 | null | 11 | null | null | 10
关键类:
@Embeddable
public class SensorKey
{
@Column
private String idsensor;
@Column
private long date;
@Column(name = "event_time")
private long eventTime;
传感器类
public class SensorEntitie implements Serializable {
@EmbeddedId
private SensorKey sensorkey;
@Column
private float temperature;
@Column
private float pressure;
@OneToMany(cascade = { CascadeType.ALL }, fetch = FetchType.EAGER)
@JoinColumns({
@JoinColumn(name = "idsensor", referencedColumnName = "idsensor"),
@JoinColumn(name = "date", referencedColumnName = "date",
insertable = false, updatable = false),
@JoinColumn(name = "event_time", referencedColumnName = "event_time",
insertable = false, updatable = false)
})
private Set<PieceEntitie> pieces;
件类:
public class PieceEntitie implements Serializable{
@Id
private String idpiece;
@Column
private double width;
@Column
private double height;
@Column
private double depth;
教程如下; https://github.com/impetus-opensource/Kundera/wiki/Polyglot-Persistence
我怎样才能建立这种关系?
【问题讨论】:
-
这个问题解决了吗?
-
不,我没有找到任何解决方案
标签: java hibernate cassandra one-to-many kundera