I look for a way how I can create a ddl for my jpa annotated entities. I prefer a pure java way for this.
If possible it would be nice to have generate the drop statemen
OpenJPA has support for this too. The OpenJPA mapping tool can create a script or create a ddl file. The ddl should work with other JPA implementations (although each vendor has a few quirks).
If you're using OpenJPA as a persistence provider you can configure OpenJPA to create the tables the first time they're needed by adding the SynchronizeMappings property to persistence.xml.
Example :
<persistence-unit name="test">
<!--
. . .
-->
<properties>
<property name="openjpa.jdbc.SynchronizeMappings"
value="buildSchema"/>
</properties>
<!--
. . .
-->
</persistence-unit>
Here's an explaination of how to use the hibernate SchemaExport class to do exactly what you want.
http://jandrewthompson.blogspot.com/2009/10/how-to-generate-ddl-scripts-from.html
Hope this helps.
Hibernate has built-in support for this. See org.hibernate.tool.hbm2ddl.SchemaExport.
DataNucleus has SchemaTool that can be invoked from java, or from the command line. It does what you require
--Andy (DataNucleus)
Export data from a database as sql
Use the liquibase opensource project
LiquiBase is an open source (LGPL), database-independent library for tracking, managing and applying database changes. It is built on a simple premise: All database changes (structure and data) are stored in an XML-based descriptive manner and checked into source control.
Generate create and drop script for given JPA entities
We use this code to generate the drop and create statements: Just construct this class with all entity classes and call create/dropTableScript.
If needed you can use a persitence.xml and persitance unit name instead. Just say something and I post the code too.
import java.util.Collection; import java.util.Properties; import org.hibernate.cfg.AnnotationConfiguration; import org.hibernate.dialect.Dialect; import org.hibernate.ejb.Ejb3Configuration; /** * SQL Creator for Tables according to JPA/Hibernate annotations. * * Use: * * {@link #createTablesScript()} To create the table creationg script * * {@link #dropTablesScript()} to create the table destruction script * */ public class SqlTableCreator { private final AnnotationConfiguration hibernateConfiguration; private final Properties dialectProps; public SqlTableCreator(final Collection> entities) { final Ejb3Configuration ejb3Configuration = new Ejb3Configuration(); for (final Class entity : entities) { ejb3Configuration.addAnnotatedClass(entity); } dialectProps = new Properties(); dialectProps.put("hibernate.dialect", "org.hibernate.dialect.SQLServerDialect"); hibernateConfiguration = ejb3Configuration.getHibernateConfiguration(); } /** * Create the SQL script to create all tables. * * @return A {@link String} representing the SQL script. */ public String createTablesScript() { final StringBuilder script = new StringBuilder(); final String[] creationScript = hibernateConfiguration.generateSchemaCreationScript(Dialect .getDialect(dialectProps)); for (final String string : creationScript) { script.append(string).append(";\n"); } script.append("\ngo\n\n"); return script.toString(); } /** * Create the SQL script to drop all tables. * * @return A {@link String} representing the SQL script. */ public String dropTablesScript() { final StringBuilder script = new StringBuilder(); final String[] creationScript = hibernateConfiguration.generateDropSchemaScript(Dialect .getDialect(dialectProps)); for (final String string : creationScript) { script.append(string).append(";\n"); } script.append("\ngo\n\n"); return script.toString(); } }