java Hibernate许多人加入

Question

我刚开始冬眠，我正在春天使用它。我有以下表格：

@Entity
@Configurable
public class Location {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long locationid;

    private String locationName;

    @ManyToOne
    private Site site;

//getters setters skipped
}

@Entity
@Configurable
public class Site {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long siteid;

    private String siteName;

    @ManyToOne
    private Country country;
    //getters setters skipped
    }

@Entity
@Configurable
public class Country {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long countryid;

    private String countryName;
    @ManyToOne
    private Region region;
    //getters setters skipped
}

@Entity
@Configurable
public class Region {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long regionid;

    private String regionName;
    //getters setters skipped
}

public class Assets {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long assetId;


    @ManyToOne
    private Location location;
    //getters setters skipped
}

我想根据地区提取所有资产。我该怎么做

如何使用区域之间的关系-->；国家-->；网站-->；定位并提取相关记录？我如何在不影响性能的情况下做到这一点

还是我应该重新设计桌子

Answer 1

您只需在类资产中通过@NamedQuery完成它：
select a from Asserts a where a.location.site.contry.regin.reginName = :reginName

希望能有所帮助