Question

我正在使用JPA 2.0，Hibernate 4.1.0.Final和Spring 3.1.1.RELEASE。我有两个实体：

@Entity
@Table(name = "user",
    uniqueConstraints = { @UniqueConstraint(columnNames = { "USER_NAME" }) }
)
public class User implements Comparable<User>, Serializable
{
    ...
    @Column(name = "first_name")
    @NotNull
    /* the first name of the User */
    private String firstName;

和

@Entity
@Table(name="code_user",
    uniqueConstraints = { 
        @UniqueConstraint(columnNames = { "SAMPLE_WORD_ID", "USER_ID" }) }
)
public class CodeUser 
{

    @Id
    @NotNull
    @GeneratedValue(generator = "uuid-strategy")
    @Column(name = "ID")
    private String id;

    @ManyToOne
    @JoinColumn(name = "CODE_ID", nullable = false, updatable = true)
    private Code code;

    @ManyToOne
    @JoinColumn(name = "USER_ID", nullable = false, updatable = true)
    private User user;

如何编写JPA / CriteriaBuilder查询以查找名字与“Dave”匹配且与代码为“abode”的代码记录绑定的所有User对象？

Answer 1

我可能错过了一个HQL语法元素

SELECT user FROM CodeUser codeUser 
    JOIN FETCH codeUser.user user
    JOIN FETCH codeUser.code code 
        WHERE user.firstName = 'Dave' AND code.value = 'abode'

假设Code的字段value包含值"abode"。您可能不需要FETCH。

您始终可以使用?等占位符或:name之类的命名占位符替换文字值，并从Query对象设置其值。

如何编写需要JOIN的JPA查询？

1 个答案: