Hibernate Tips: How to create a database setup script based on entity mappings

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Question:

I want to use a database setup script instead of Hibernate’s schema generation. What’s the easiest way to create this script for an existing entity model?

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Solution:

JPA 2.1 introduced a schema generation features which can setup your database or export the generated commands to a file. You just have to set the following configuration parameters in your persistence.xml file to activate it:

javax.persistence.schema-generation.scripts.action

Defines which scripts the persistence provider shall create. You can choose between none, create, drop-and-create, drop. A script target needs to be defined for each script to be created.

javax.persistence.schema-generation.scripts.create-target

Defines the target location of the create script generated by the persistence provider as a file URL or a java.IO.Writer.

javax.persistence.schema-generation.scripts.drop-target

Defines the target location of the drop script generated by the persistence provider as a file URL or a java.IO.Writer.

Here you can see a persistence.xml configuration that generates a create and a drop script based on the entity mapping information.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.1" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">

<persistence-unit name="EFS2015-persistence-unit" transaction-type="JTA">

<description>Forge Persistence Unit</description>

<provider>org.hibernate.ejb.HibernatePersistence</provider>

<jta-data-source>java:jboss/datasources/ExampleDS</jta-data-source>

<exclude-unlisted-classes>false</exclude-unlisted-classes>

<properties>

<property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect"/>




<property name="javax.persistence.schema-generation.scripts.action" value="drop-and-create"/>

<property name="javax.persistence.schema-generation.scripts.create-target" value="./create.sql"/>

<property name="javax.persistence.schema-generation.scripts.drop-target" value="./drop.sql"/>

</properties>

</persistence-unit>

</persistence>

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