Question

我的实体类：

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="APP_INSTANCE")
public class ApplicationEntity {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="INSTANCE_KEY")
    private int INSTANCE_KEY;
 //other code 
}

我的表结构：

CREATE TABLE "APP_INSTANCE" 
("INSTANCE_KEY" NUMBER NOT NULL ENABLE, 
"SYS_ID" VARCHAR2(255) , 
"NAME" VARCHAR2(255) , 
"ENV" VARCHAR2(50) , 
PRIMARY KEY ("APP_INSTANCE_KEY") ENABLE
 )

我正在使用Spring 3，Hibernate 4和oracle database.While运行我的应用程序iam gettin gbelow错误：

03:23:07,380 INFO  [STDOUT] Hibernate: insert into USER.APP_INSTANCE (SYS_ID, NAME, ENV) values (?, ?, ?)
03:23:08,271 INFO  [STDOUT] WARN : org.hibernate.engine.jdbc.spi.SqlExceptionHelper - SQL Error: 1400, SQLState: 23000
03:23:08,271 INFO  [STDOUT] ERROR: org.hibernate.engine.jdbc.spi.SqlExceptionHelper - ORA-01400: cannot insert NULL into ("USER"."APP_INSTANCE"."INSTANCE_KEY")
03:23:08,271 INFO  [STDOUT] Exception in saving..
03:23:08,271 ERROR [STDERR] org.hibernate.exception.ConstraintViolationException: could not execute statement
03:23:08,271 ERROR [STDERR]     at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:74)
03:23:08,271 ERROR [STDERR]     at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
03:23:08,271 ERROR [STDERR]     at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:124)

我也试过了GenerationType.AUTO，但后来我得到了sequence not found这样的东西。

请帮忙。我知道这个问题与@GeneratedValue有关。请告诉我上面的表oad oracle数据库的值。

Answer 1

您可以使用GenericGenerator类的休眠。

@Id
@GenericGenerator(name = "increment", strategy = "increment")
@GeneratedValue(generator = "increment")
private int INSTANCE_KEY;

Answer 2

在oracle数据库中创建序列：并注释id以使用此序列：

CREATE SEQUENCE SEQ_APP_INSTANCE
 START WITH     1
 INCREMENT BY   1
 NOCACHE
 NOCYCLE;

Answer 3

在INSTANCE_KEY字段中设置此项：

@Id
@Column(name="INSTANCE_KEY")
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "seqInstanceKey")
@SequenceGenerator(name = "seqInstanceKey", sequenceName = "SEQ_INSTANCE_KEY", allocationSize = 1)
private int INSTANCE_KEY;

在您的数据库中添加一个名称为＆＃39; SEQ_INSTANCE_KEY＆＃39;的序列。财产增量乘以＆＃39; 1＆＃39;

Hibernate：strategy = oracle的GenerationType值

3 个答案: