Question

Say I have a table like so:

CREATE TABLE big_table (UUID varchar(32) not null, ... );

I have a query on the table that I can’t express as an HQL or Criteria query. I am trying to set up the query as view in Oracle, like so:

CREATE VIEW big_table_view AS SELECT bt.* FROM big_table bt
    LEFT OUTER JOIN ...
        -- (multicolumn subselect over big_table for some historical stuff)
    WHERE ...

I am trying to map the same Java class to both the table and the view. That would be really cool because then I can run the same Criteria queries against both, etc.

My problem is that I can’t come up with an HBM mapping file that doesn’t wreak havoc with my HSQLDB test code. My test setup is a typical Maven/Spring test setup with hibernate.hbm2ddl.auto set to create-drop so that Hibernate creates the HSQLDB schema on the fly for testing.

My mapping file currently looks like this:

<hibernate-mapping>
    <class name="com.example.BigPojo" entity-name="bigPojo"
            table="big_table">
        &commonPropertiesEntity;
    </class>

    <class name="com.example.BigPojo" entity-name="bigPojoView"
            table="big_table_view">
        &commonPropertiesEntity;
    </class>
</hibernate-mapping>

…when I run my tests, they blow up all over the place because HSLQDB is trying to create a table called big_table_view with all the same foreign key constraints, indices, etc. I’m trying to fix the schema after it gets created via a database-object element like this:

<database-object>
    <create>
        DROP TABLE big_table_view CASCADE;
        CREATE VIEW big_table_view...
    </create>
    <drop>
        DROP VIEW big_table_view IF EXISTS;
    </drop>
    <dialect-scope name="org.hibernate.dialect.HSQLDialect" />
</database-object>

…but there’s still something breaking and I’m still wading through trying to figure it out. Is there a way to tell Hibernate to exclude the bigPojoView entity from hbm2ddl? Is there a better way to do this mapping generally? I’m open to any advice…

Answer 1

There’s no easy way to exclude a table from hbm2ddl. You can, however, map your view via Hibernate’s subselect: see footnote #20 under 5.1.1.

Something like:

<class name="com.example.BigPojo" entity-name="bigPojoView"
    <subselect>
      ... your view definition here ...
    </subselect>
    <synchronize table="big_table"/>
    <id name="UUID"/>
    ...
</class>