Java 使用JOIN实现JPA请求
我有以下3个实体: 付款交易:Java 使用JOIN实现JPA请求,java,jpa,jpa-2.0,hibernate-jpa,Java,Jpa,Jpa 2.0,Hibernate Jpa,我有以下3个实体: 付款交易: @Entity @Table(name = "payment_transactions") public class PaymentTransactions implements Serializable { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "id", unique = true, updatable = false, nullab
@Entity
@Table(name = "payment_transactions")
public class PaymentTransactions implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, updatable = false, nullable = false)
private int id;
.....
}
@Entity
@Table(name = "wpf_payment_payment_transactions")
public class WpfPaymentPaymentTransactions implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, updatable = false, nullable = false, length = 3)
private int id;
@Column(length = 4)
private Integer wpf_payment_id;
@Column(length = 4)
private Integer payment_transaction_id;
.....
}
WPF付款:
@Entity
@Table(name = "wpf_payments")
public class WpfPayments implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, updatable = false, nullable = false)
private int id;
............
}
WPF付款交易:
@Entity
@Table(name = "payment_transactions")
public class PaymentTransactions implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, updatable = false, nullable = false)
private int id;
.....
}
@Entity
@Table(name = "wpf_payment_payment_transactions")
public class WpfPaymentPaymentTransactions implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, updatable = false, nullable = false, length = 3)
private int id;
@Column(length = 4)
private Integer wpf_payment_id;
@Column(length = 4)
private Integer payment_transaction_id;
.....
}
我使用这些SQL请求获取基于id的正确数据:
SELECT `payment_transactions`.* FROM `payment_transactions` INNER JOIN `wpf_payment_payment_transactions` ON `payment_transactions`.`id` = `wpf_payment_payment_transactions`.`payment_transaction_id` WHERE `wpf_payment_payment_transactions`.`wpf_payment_id` = 75 ORDER BY `payment_transactions`.`id` ASC LIMIT 1
SELECT `payment_transactions`.* FROM `payment_transactions` INNER JOIN `wpf_payment_payment_transactions` ON `payment_transactions`.`id` = `wpf_payment_payment_transactions`.`payment_transaction_id` WHERE `wpf_payment_payment_transactions`.`wpf_payment_id` = 75
是否有某种方法可以使用JPA查询实现这些SQL请求?如果您使用的是JPA 2.0,则无法在查询中使用
JPQL
,因为您无法使用ON
子句
一种解决方案是在实体WpfPaymentPaymentTransactions
上实现双向映射,
PaymentTransactions
要能够加入:
@Entity
@Table(name = "payment_transactions")
public class PaymentTransactions implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, updatable = false, nullable = false)
private int id;
@OneToOne(mappedBy="paymentTransactions") //or OneToMany depending on your model
private WpfPaymentPaymentTransactions wpfPaymentPaymentTransactions;
}
@Entity
@Table(name = "wpf_payment_payment_transactions")
public class WpfPaymentPaymentTransactions implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", unique = true, updatable = false, nullable = false, length = 3)
private int id;
@ManyToOne
@JoinColumn(name="wpf_payment_id")
private PaymentTransactions paymentTransactions;
}
然后可以像这样连接两个实体:
SELECT t FROM PaymentTransactions t
INNER JOIN WpfPaymentPaymentTransactions wppt
从JPA2.1开始,您可以使用JPQL查询添加ON
子句。因此,对于第一个查询,它将如下所示:
SELECT t FROM PaymentTransactions t
INNER JOIN WpfPaymentPaymentTransactions wppt
ON t.id = wppt.paymentTransactionId`
WHERE wppt.wpfPaymentId = :param
ORDER BY t.id ASC LIMIT 1
希望有帮助 你想要那些
SQL
查询的JPQL
版本,还是想用JPA
执行它们?请给我看看JPQL版本好吗?我使用最新的JPA(spring boot starter数据JPA-spring boot starter父版本2.1.2.RELEASE)因此,您可以在响应中使用带有类似jpql的on
子句。你知道我如何修复它吗?你能告诉我你是如何执行jpql查询的吗?好的。此外,如果它是有帮助的,请投票或标记为回应。谢谢