Recently, I wanted to keep the change history of entities saved via Hibernate and also have a versioned database. Hence, I used Hibernate Envers and Liquibase.
The tables for envers, both the revinfo table and the _AUD tables for each entity, have to be included in the changeset of Liquibase:
<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.1.xsd">
<property name="long_type" value="bigint" dbms="postgresql"/>
<property name="long_type" value="long" dbms="h2"/>
<changeSet id="CreateBasicSchema" author="Steven Schwenke">
<createSequence sequenceName="hibernate_sequence" startValue="0" incrementBy="1"/>
<createTable tableName="revinfo">
<column name="rev" type="integer" autoIncrement="true">
<constraints primaryKey="true"/>
</column>
<column name="revtstmp" type="bigint"/>
</createTable>
<createTable tableName="stuff">
<column name="id" type="${long_type}">
<constraints nullable="false" unique="true" primaryKey="true"/>
</column>
<column name="text" type="varchar(36)">
<constraints nullable="false"/>
</column>
</createTable>
<createTable tableName="stuff_aud">
<column name="id" type="${long_type}">
<constraints nullable="false" />
</column>
<column name="rev" type="integer">
<constraints referencedTableName="revinfo"
foreignKeyName="fk_brands_stuff_revinfo"
referencedColumnNames="rev"
nullable="false"/>
</column>
<column name="revtype" type="integer">
<constraints nullable="false"/>
</column>
<column name="stuff" type="varchar(36)">
<constraints nullable="true"/>
</column>
</createTable>
<addPrimaryKey tableName="stuff_aud" columnNames="id, rev" />
</changeSet>
</databaseChangeLog>The autoIncrement=”true” in the revinfo table is quite important. Without it, new revisions don’t have an ID and this exception occurs:
o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 23502, SQLState: 23502
o.h.engine.jdbc.spi.SqlExceptionHelper : NULL nicht zulässig für Feld "REV"
NULL not allowed for column "REV"; SQL statement:
/* insert org.hibernate.envers.DefaultRevisionEntity */ insert into revinfo (rev, revtstmp) values (null, ?) [23502-200]
org.springframework.dao.DataIntegrityViolationException: could not execute statement ...The best way to prevent this exception from happening is the mentionend autoIncrement. However, it’s also possible to create an entity for the revision:
import org.hibernate.envers.RevisionEntity;
import org.hibernate.envers.RevisionNumber;
import org.hibernate.envers.RevisionTimestamp;
import javax.persistence.*;
@Entity
@RevisionEntity
@Table(name = "revinfo")
public class Revision {
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
@Column(nullable = false, name = "REV")
@RevisionNumber
private long rev;
@Column(name = "revtstmp")
@RevisionTimestamp
private long timestamp;
public long getRev() {
return rev;
}
public void setRev(long rev) {
this.rev = rev;
}
public long getTimestamp() {
return timestamp;
}
public void setTimestamp(long timestamp) {
this.timestamp = timestamp;
}
}