Using Liquibase and Spring Boot

Question

I have a Spring Boot application and want to use Liquibase to generate the changelogs for my JPA entities. However, I encounter different issues, depending on my approach.

My first approach is to use the diff goal of the maven plugin. The url is my H2 development database with the H2 driver and the reference URL is something like "hibernate:spring:myBasePackage.myEntityPackage?dialect=org.hibernate.dialect.H2Dialect" with the driver "liquibase.ext.hibernate.database.connection.HibernateDriver". In that case Liquibase seems to recognize my entities, but prints the differences to the console. Also the differences do not have the form of a changelog file.
My second approach would be to use the generateChangeLog goal of the maven plugin. In this case my url is "hibernate:spring:myBasePackage.myEntityPackage?dialect=org.hibernate.dialect.H2Dialect" with the driver "liquibase.ext.hibernate.database.connection.HibernateDriver. In this case I am getting an error "Unable to resolve persistence unit root URL: class path resource [] cannot be resolved to URL because it does not exist". This error can be found in both the Spring an the Liquibase issue trackers, but it seems like it is always said that this error is already fixed.
My third approach is basically like the second, but in this case I am using a "hibernate:classic" url with an implementation of "CustomClassicConfigurationFactory", which registers my annotated classes explicitly. This does work. However, in this case I have to do this in my application-jar. I have to add my application-jar as a dependency for the maven-plugin. Thus I have to build my application-jar (and install it to the local Maven repository), before I can generate the changelogs. This seems to be cumbersome.

My questions are:

Is there an easier way to generate the changelogs for JPA entities in a Spring boot based application?
Why are the first two approaches not working?
Is there a way to simplify the third approach?

I am using:

Spring Boot 1.5.4.RELEASE
Liquibase-Hibernate4 3.6
Liquibase 3.5.3

Many thanks in advance.

JITHIN_PATHROSE JITHIN_PATHROSE · Accepted Answer · 2019-04-02T12:05:08

In the first approach using liquibase:diff , the change set for the entities (create table change set) will not be generated since liquibase do not assume new jpa entity as change.

In the second approach generateChangeLog, it generates the change log from the given data base.It won't look into your jpa entities.

In order to generate the ddl scripts for your jpa entities , just submit the following to your jpa properties

<property key="javax.persistence.schema-generation.scripts.action">drop-and-create</property>
<property key="javax.persistence.schema-generation.scripts.create-target">./ddl/create.sql</property>
<property key="javax.persistence.schema-generation.scripts.drop-target">./ddl/drop.sql</property>

The above will generate the scripts the ddl folder under the root folder.

You can check the other properties here https://thoughts-on-java.org/standardized-schema-generation-data-loading-jpa-2-1/

Using Liquibase and Spring Boot

1 Answers