Bug 213907 Provide a copy constructor for SubqueryDefinition.
Engine need a copy constructor to generate a SubqueryDefinition from an ISubqueryDefinition and change the name of the query.
data/org.eclipse.birt.report.data.adapter/src/org/eclipse/birt/report/data/adapter/impl/DataRequestSessionImpl.java
}
	/*
	 * @see org.eclipse.birt.report.data.adaptor.impl.IDataRequestSession#getQueryResults(java.lang.String)
	 */
	public IQueryResults getQueryResults( String queryResultID )
			throws BirtException
	{
		return dataEngine.getQueryResults( queryResultID );
	}
	/*
	 * @see org.eclipse.birt.report.data.adaptor.impl.IDataRequestSession#clearCache(org.eclipse.birt.data.engine.api.IBaseDataSourceDesign,
	 *      org.eclipse.birt.data.engine.api.IBaseDataSetDesign)
	 */
	public void clearCache( IBaseDataSourceDesign dataSource,
			IBaseDataSetDesign dataSet ) throws BirtException
	{
		dataEngine.clearCache( dataSource, dataSet );
	}
	/*
	 * @see org.eclipse.birt.report.data.adaptor.impl.IDataRequestSession#prepare(org.eclipse.birt.data.engine.api.IQueryDefinition,
	 *      java.util.Map)
	 */
	public IPreparedQuery prepare( IQueryDefinition query, Map appContext )
			throws BirtException
	{
		if ( appContext == null )
			
			appContext = sessionContext.getAppContext( );
		return dataEngine.prepare( query, appContext );
	}