Storing created & last updated properties

Created & Last Updated properties

Whenever u're dealing with some accounts, transactions, product items, notes, reviews, etc. it's always useful to know when those where created & last updated/edited/modified.

Notice, that it's always better to fill such properties on the Back-End side rather than on the Front-End. Otherwise, the client can exchange the data & try to store some invalid values. Actually even if the client will send the valid dates, those will not reflect exact time when the data was added in the DB. ## Auto-fill created & updated Dates with JPA There are three JPA annotations exist for this purpose: * **@PrePersist** - Executed before the entity manager persist operation is actually executed or cascaded. This call is synchronous with the persist operation. * **@PreUpdate** - Executed before the database UPDATE operation. * **@Temporal** - Set the temporal type to timestamp. Otherwise, Hibernate could store date without hours, minutes and seconds *(only day, month and year)*. Here is the abstract code example: import java.util.Date; import javax.persistence.Column; import javax.persistence.MappedSuperclass; import javax.persistence.PrePersist; import javax.persistence.PreUpdate; import javax.persistence.Temporal; import javax.persistence.TemporalType; @MappedSuperclass public abstract class AbstractTimestampEntity { @Temporal(TemporalType.TIMESTAMP) @Column(name = "created", nullable = false) private Date created; @Temporal(TemporalType.TIMESTAMP) @Column(name = "updated", nullable = false) private Date updated; @PrePersist protected void onCreate() { updated = created = new Date(); } @PreUpdate protected void onUpdate() { updated = new Date(); } } Note: For Enterprise applications you have to deal with cases when few transactions update the same data. So, you have to use versions & locking in addition. ---- ## see Also * [Hibernate - Entity listeners & Callbacks](https://docs.jboss.org/hibernate/entitymanager/3.5/reference/en/html/listeners.html) * [Hibernate - Transactions and Concurrency](https://docs.jboss.org/hibernate/orm/3.3/reference/en/html/transactions.html) * [Oracle - Persistence](https://docs.oracle.com/javaee/7/tutorial/partpersist.htm) * [Hibernate and last modified date](http://notatube.blogspot.com.ee/2010/03/hibernate-using-event-listener-to-set.html) * [What-When-How - Transactions and Concurrency in Hibernate](http://what-when-how.com/hibernate/transactions-and-concurrency-hibernate/)