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[英]Spring Entity Manager with H2 error: NULL not allowed for column “EMPLOYEE_ID” error
[英]Spring boot error: NULL not allowed for column “ID” error
我的Spring Boot應用程序啟動時一直出現此錯誤
Caused by: org.h2.jdbc.JdbcSQLIntegrityConstraintViolationException: NULL not allowed for column "ID"; SQL statement:
insert into bookings(bookings_name) values('Kris') [23502-199]
data.sql有
insert into bookings(bookings_name) values('Kris');
insert into bookings(bookings_name) values('Martin');
而且我相信我有注釋,以便自動生成@Id
@Entity
class Bookings {
@Id
@GeneratedValue
@Column(name = "id", updatable = false, nullable = false)
private Long id;
private String BookingsName;
public Long getId() {
return id;
}
public String getBookingsName() {
return BookingsName;
}
public Bookings(String BookingsName) {
super();
this.BookingsName = BookingsName;
}
@Override
public String toString() {
return "Bookings [id=" + id + ", BookingsName=" + BookingsName + "]";
}
}
我剛剛開始學習Spring Boot,在網上找到的每個示例似乎都無法轉化為我這里的瑣碎示例。
完整的應用程序
import java.util.Collection;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
@Component
class BookingsCommandLineRunner implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
}
}
interface BookingsRepository extends JpaRepository<Bookings, Long> {
Collection<Bookings> findByBookingsName(String BookingsName);
}
@RestController
class BookingsRestController {
@Autowired
BookingsRepository BookingsRepository;
@RequestMapping("/Bookingss")
Collection<Bookings> Bookingss() {
return this.BookingsRepository.findAll();
}
}
@Entity
class Bookings {
@Id
@GeneratedValue
@Column(name = "id", updatable = false, nullable = false)
private Long id;
private String BookingsName;
public Long getId() {
return id;
}
public String getBookingsName() {
return BookingsName;
}
public Bookings(String BookingsName) {
super();
this.BookingsName = BookingsName;
}
@Override
public String toString() {
return "Bookings [id=" + id + ", BookingsName=" + BookingsName + "]";
}
}
您使用哪個數據庫? 我認為默認策略可能並不總是有效。
嘗試在實體聲明中使用其他策略:
@Entity
class Bookings {
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
@Column(name = "id", updatable = false, nullable = false)
private Long id;
我認為關於Spring / JPA和DBMS ID的生成這里有一個困惑。 對純數據庫運行SQL(無論是否通過Java代碼),就像硬編碼的“插入預訂(bookings_name)值('Kris');”中一樣 不會在乎是否將實體的ID字段注釋為@GeneratedValue。
要插入預訂,您可以:
希望能有所幫助,
再見
您需要更改數據庫,以便ID列是標識/自動遞增列,即,該值將由H2管理,並且客戶端將不會為新記錄指定值。
完成此操作后,就應該加載data.sql中的記錄,而不會出現任何問題。
對於JPA實體,您需要進行以下更新以告知您的JPA提供者ID由數據庫管理:
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", updatable = false, nullable = false)
private Long id;
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