Question

我有四节课; UserGroup，UserAccount，Role，UserGroupRoleRelation和我的数据库是IBM DB2

@Entity
@Table(name = "USER_GROUP")
public class UserGroup implements Serializable {

    @Id
    @Column(name = "USER_GROUP_ID")
    @GeneratedValue
    private Long id;
......
..
    @OneToMany(mappedBy = "userGroup", cascade = CascadeType.ALL, orphanRemoval = true)
    private List<UserGroupRoleRelation> userAccountsRole = new ArrayList<UserGroupRoleRelation>();


}




@Entity
@Table(name = "ROLE")
public class Role implements Serializable {

    @Id
    @Column(name = "ROLE_ID")
    @GeneratedValue
    private Long id;

    ......

    @OneToMany(mappedBy = "role")
    private List<UserGroupRoleRelation> userAccountInGroup = new ArrayList<UserGroupRoleRelation>();


}


@Entity
@Table(name = "USER_GROUP_ROLE_LINE", uniqueConstraints = @UniqueConstraint(columnNames = { "ROLE_ID", "USER_GROUP_ID" }))
public class UserGroupRoleRelation {

    @Id
    @GeneratedValue
    @Column(name = "RELATION_ID")
    private Long relationId;

    @ManyToMany(cascade = CascadeType.ALL)
    @JoinTable(name = "USER_ACCOUNT_USER_GROUP_ROLE_LINE", joinColumns = { @JoinColumn(name = "RELATION_ID") }, inverseJoinColumns = { @JoinColumn(name = "USER_ID") }, uniqueConstraints = @UniqueConstraint(columnNames = { "USER_ID", "RELATION_ID" }))
    private List<UserAccount> userAccountList = new ArrayList<UserAccount>();

    @ManyToOne
    @JoinColumn(name = "USER_GROUP_ID")
    private UserGroup userGroup;

    @ManyToOne
    @JoinColumn(name = "ROLE_ID")
    private Role role;
}


@Entity
@Table(name = "USER_ACCOUNT")
public class UserAccount implements Serializable {

    @Id
    @Column(name = "USER_ID")
    @GeneratedValue
    private Long id;
.....

    @ManyToMany(mappedBy = "userAccountList", cascade = CascadeType.ALL)
    private List<UserGroupRoleRelation> rolesInGroup = new ArrayList<UserGroupRoleRelation>();
}

我想找到一个useraccount的用户组，我准备了一个带有标准的方法。它就像;

    @Override
    @Transactional
    public List<UserGroup> findUserGroupOf(UserAccount userAccount) {
        Criteria criteria = getSession().createCriteria(UserGroup.class);
        criteria.createAlias("userAccountsRole", "userAccountsRole");
        criteria.add(Restrictions.eq("userAccountsRole.userAccountList", userAccount));
        return criteria.list();

    }

但是当我试图获得该方法的结果时，DB2给了我DB2 SQL Error: SQLCODE=-313, SQLSTATE=07004, SQLERRMC=null, DRIVER=3.63.75

可能是关于在多对多关系中创建别名。我不知道我该怎么做才能在很多人身上创建别名。如何获得该功能的结果？

感谢

Answer 1

    @Override
    @Transactional
    public List<UserGroup> findUserGroupOf(UserAccount userAccount) {
        Criteria criteria = getSession().createCriteria(UserGroup.class);
        criteria.createAlias("userAccountsRole", "userAccountsRole");
        criteria.createAlias("userAccountsRole.userAccountList", "userAccountList");
        criteria.add(Restrictions.eq("userAccountList.id", userAccount.getId()));
        return criteria.list();

    }

它对我有用。我是指“id”的标准。但是我不明白为什么当有ManyToMany列表

时我无法检查对象而不是id的相等性

Answer 2

不是创建别名。您正在将一个对象传递给hibernate，它无法制定任何标准。您需要为它创建双向映射。否则，如果您的要求只是获取特定UserGroup类的UserAccountList列表，则可以按照以下代码。

@Override
@Transactional
public List<UserGroup> findUserGroupOf(long userGroupId) {
    Criteria criteria = getSession().createCriteria(UserGroup.class);
    criteria.add(Restrictions.eq("id",userGroupId));
    criteria.createAlias("userAccountsRole", "uar");
    criteria.setFetchMode("uar.userAccountList",FetchMode.JOIN);
    return criteria.list();

}

Hibernate在很多对很多列表中创建别名

2 个答案: