spring data jpa auditing failure for many to many mapping - spring-data

Question

Hi I am getting hard time in saving one of the manytomany mapping entity due to an auditing issue.
We are using spring data with base entity to manage the audit information.
It all works fine but for one manytomany mapping I am getting sql exception
Field 'createdon' doesn't have a default value.
Please find below my config
import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;
import com.minda.iconnect.cache.CacheableEntity;
/**
* Simple JavaBean domain object with an id property. Used as a base class for objects needing this property.
*
*/
#SuppressWarnings("serial")
#MappedSuperclass
public class BaseEntity implements TimeStampedAuditable, Serializable, CacheableEntity{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
protected Long id;
#Column(name = "createdon", nullable = false)
protected Date createdOn;
#Column(name = "updatedon")
protected Date updatedOn;
public void setId(Long id) {
this.id = id;
}
public Long getId() {
return id;
}
public boolean isNew() {
return (this.id == null);
}
#Override
public Date getCreatedOn() {
return createdOn;
}
#Override
public void setCreatedOn(Date createdOn) {
this.createdOn = createdOn;
}
#Override
public Date getUpdatedOn() {
return updatedOn;
}
#Override
public void setUpdatedOn(Date updatedOn) {
this.updatedOn = updatedOn;
}
#Override
public String getCacheKey() {
return getId() == null ? "null" : String.valueOf(getId());
}
}
Below is mentioned sql for table creation:
create table role (
id bigint primary key not null auto_increment,
name varchar(255) not null,
role_code varchar(31) not null,
createdon datetime not null,
updatedon datetime
) engine=innodb;
create table user (
id bigint primary key not null auto_increment,
username varchar(255),
firstname varchar(255) not null,
lastname varchar(255) not null,
email varchar(255) not null,
createdon datetime not null,
updatedon datetime
) engine=innodb;
create table user_role (
id bigint primary key not null auto_increment,
roles_id bigint not null references role(id),
user_id bigint not null references user(id),
createdon datetime not null,
updatedon datetime
) engine=innodb;
I am using below code to save a user with an already existing role:
#Transactional
#Override
public User createUser(User user) {
Role role = roleService.getRoleByCode("Some Role");
List<Role> roles = new ArrayList<Role>();
roles.add(role);
user.setRoles(roles);
User savedUser = userRepository.save(user);
}
while saving I get sql error that the createdon field does not have a default value.
Since the relation is a self managed entity by jpa, I am confused that what needs to be done to make it audit-able.
Thanks,
Rohit Mishra

Answer 1

you are getting that exception because of the nullable = false, You can use a Jpa Entity Listener,
#PrePersist
protected void persistCreatedOn(){
this.createdOn = Calendar.getInstance().getTime();
}
this way JPA will set the createdOn just before persisting your Entity.

Answer 2

After analyzing the problem and spending some time we realized that the relations should not extend base entity and they need not to be audited the parent entity gives the information required. Its the job of the underneath orm to take care of the the relations.