Can Hibernate Schema generation be used to generate DDL without database connection

Question

I'd like to use Hibernate' schema generation to generate DDL for a database that I cannot access directly from my PC, just using hibernate config files. I'd like to skip, if possible, the installation of a local oracle database. Can hibernate generate DDL for a "theoretical" database of the appropriate dialect, version, etc., or is this a pipe dream?

Are there other tools that can do this?

Answer 1

1. You can either use an In-memory database during testing phase;

   hibernate.hbm2ddl.auto="update"

2. Or you can generate your DDL using the hibernatetool from Maven:

   <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-antrun-plugin</artifactId>
       <executions>
           <execution>
               <id>generate-test-sql-scripts</id>
               <phase>generate-test-resources</phase>
               <goals>
                   <goal>run</goal>
               </goals>
               <configuration>
                   <tasks>
                       <property name="maven_test_classpath" refid="maven.test.classpath"/>
                       <path id="hibernate_tools_path">
                           <pathelement path="${maven_test_classpath}"/>
                       </path>
                       <property name="hibernate_tools_classpath" refid="hibernate_tools_path"/>
                       <taskdef name="hibernatetool"
                                classname="org.hibernate.tool.ant.HibernateToolTask"/>
                       <mkdir dir="${project.build.directory}/test-classes/hsqldb"/>
                       <hibernatetool destdir="${project.build.directory}/test-classes/hsqldb">
                           <classpath refid="hibernate_tools_path"/>
                           <jpaconfiguration persistenceunit="testPersistenceUnit"
                                             propertyfile="src/test/resources/META-INF/spring/jdbc.properties"/>
                           <hbm2ddl drop="false" create="true" export="false"
                                    outputfilename="create_db.sql"
                                    delimiter=";" format="true"/>
                           <hbm2ddl drop="true" create="false" export="false"
                                    outputfilename="drop_db.sql"
                                    delimiter=";" format="true"/>
                       </hibernatetool>
                   </tasks>
               </configuration>
           </execution>
       </executions>
   </plugin>
   

   This Maven plugin will generate the following DDL files:

   • create_db.sql (containing all DDL statements for creating the DB)
   • drop_db.sql (containing all DDL statements for dropping the DB)

Answer 2

As of hibernate-tools 5.3 you can also use the integrated hibernate-tools-maven-plugin. There you should also find documentation on how to use it.

Unfortunatelly the maven-site with detailed description of the parameters/goals for it is not yet published but a little bit older version of it is available here.

There would be a PR (#842) that would allow for the site to be generated... unfortunatelly it hasn't found its way in yet.

Answer 3

Please try my new plugin which addresses this exact problem which has also plagued me for many years.

https://github.com/archiecobbs/hibernate-jpa-schemagen