@TableGenerator : how to use

Question

i will try to generate the primary keys using table generator. but when i insert the 6 records in my table, the primaryKey table show only one on value. here is the following code

My Entity class

package com.generatorvaluetest.domain;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.TableGenerator;

@Entity
public class Snufu {
private int autoId;
private int identityId;
private int sequenceId;
private int tableId;
private String name;
public int getAutoId() {
    return autoId;
}
public void setAutoId(int autoId) {
    this.autoId = autoId;
}
public int getIdentityId() {
    return identityId;
}
public void setIdentityId(int identityId) {
    this.identityId = identityId;
}
public int getSequenceId() {
    return sequenceId;
}
public void setSequenceId(int sequenceId) {
    this.sequenceId = sequenceId;
}

@Id
@TableGenerator(name="tg" , table="pk_table", pkColumnName="name" , 
valueColumnName="vlaue" , allocationSize=10)
@GeneratedValue(strategy=GenerationType.TABLE , generator="tg")
public int getTableId() {
    return tableId;
}
public void setTableId(int tableId) {
    this.tableId = tableId;
}

public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
  }

This is my main class

 package com.generatorvaluetest.main;

 import org.hibernate.HibernateException;
 import org.hibernate.Session;

 import com.generatorvaluetest.domain.Snufu;
 import com.generatorvaluetest.util.HibernateUtil;

 public class GeneratorValueTest {
public static void main(String[] args) throws HibernateException{
    HibernateUtil.recreateDatabase();
    Session session = HibernateUtil.beginTransaction();
    for(int i = 0 ; i< 5 ; i++){
        Snufu snufu = new Snufu();
        snufu.setName("jimmy"+i);
        session.saveOrUpdate(snufu);
    }

    new Thread(new Runnable() {

        @Override
        public void run() {
            Session session = HibernateUtil.beginTransaction();
            Snufu snufu = new Snufu();
            snufu.setName("jimmykalra");
            session.saveOrUpdate(snufu);
            HibernateUtil.commitTransaction();
        }
    }).start();
    HibernateUtil.commitTransaction();
}
  }

in database when i select the values from pk_table the values are

|name | value|
|snuf | 1    |

but in snufu tables there are 6 records

Solution 1

The value for valueColumnName is mispelled as compared with table specified. Also haven't mentioned which row to refer for fetching key, identified by column value(pkColumnValue).

Below is the sample code & can refer TableGenerator documentation, for further reference.

TableGenerator(name="tg" , table="pk_table", pkColumnName="value" , 
valueColumnName="name" , pkColumnValue = "snuf", allocationSize=10)

Solution 2

It can be misleading to see the value 1 in your @TableGenerator table while 6 records have already been inserted in your @Entity table, but the explanation is quite simple. You've set up your @TableGenerator with an allocationSize=10. What that means is: Hibernate has already pre-allocated IDs from 1 to 9 and once the 9th record is inserted in your @Entity table or you restart your application, the next generated ID will be 10 (pk_table.value * allocationSize). Also, before a row with ID=10 or the next row after application restart is inserted, pk_table.value is incremented by 1, so when this next chunk of 10 is depleted or you restart the application again, ID generation will resume at 20 (2 * 10).