Hibernate having issues with sequence object - unable to call next val

问题

I am using hibernate entity - and sequence generator with it.

My database is Oracle 12c.

In my sequence generator - it fetches value which is already present in table.

I tried looking out for issue - found one simmilar thread Hibernate sequence nextVal resolved but not used (Oracle)

But still it did not help . The issue am facing is - it works some times and it does not work some times

Below is my code snippet -

@Entity
@Table(name="TABLE_NAME", schema = "SCHEMA")
@SequenceGenerator(name="TABLE_ID_SEQ_GEN", sequenceName="SCHEMA.TABLE_ID_SEQ",allocationSize=1)
public class ImportTransactionDataEntity {

    @Id
    @Column(name="TABLE_ID",unique=true,nullable=false)
    @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="TABLE_ID_SEQ_GEN" )
    private int IDColumnPk;

ANy help is appreciated , thank you :)

回答1:

According to Oracle documentation, the @SequenceGenerator should be added to the field, not to the class:

https://docs.oracle.com/cd/E16439_01/doc.1013/e13981/cmp30cfg001.htm#BCGGHADG

so something like:

@Entity
@Table(name="TABLE_NAME", schema = "SCHEMA")

public class ImportTransactionDataEntity {

    @Id
    @Column(name="TABLE_ID",unique=true,nullable=false)
    @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="TABLE_ID_SEQ_GEN" )
    @SequenceGenerator(name="TABLE_ID_SEQ_GEN", sequenceName="SCHEMA.TABLE_ID_SEQ",allocationSize=1)
    private int IDColumnPk;

This works for me.

回答2:

try this

@Entity
@Table(name="TABLE_NAME")
@SequenceGenerator(name="TABLE_ID_SEQ_GEN",sequenceName="TABLE_ID_SEQ",allocationSize=1)
public class ImportTransactionDataEntity {

@Id
@Column(name="TABLE_ID",unique=true,nullable=false)
@GeneratedValue(strategy=GenerationType.AUTO,generator="TABLE_ID_SEQ_GEN" )
private int IDColumnPk;

it is stored in you database like this the last nummber is the last id used so dont worry about loosing count cause the database does that for you

回答3:

well finally - i had come to a solution that i was already using oracle 12 C - decide to go with Identity column on the table it self .

NOTE - but the identity column is not available before Oracle 12c .

I ended up getting better performance also with some fraction , so this work around was sigh of relief for me

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "TABLE_ID", updatable = false, nullable = false)
private int IDColumnPk;

来源：https://stackoverflow.com/questions/52055666/hibernate-having-issues-with-sequence-object-unable-to-call-next-val

标签

java

hibernate