Bug 191627 [Regression]Exception occurs when first preview the joint dataset[0706]
Description: [Regression]Exception occurs when preview the flatfile and sampledb joint dataset[0706] Build number: 2.2.0.v20070608-0630 Steps to reproduce: 1, New a flatfile dataset 2, New a CUSTOMER dataset 3, Join two datasets with STATE column 4, Preview in dataset Expected result: Preview successfully Actual result: Exception occurs Error log: A BIRT exception occurred. Plug-in Provider:Eclipse.org Plug-in Name:BIRT Data Engine Plug-in ID:org.eclipse.birt.data Version:2.2.0.v20070607-1421 Error Code:data.engine.ColumnBindingReferToInexistColumn Error Message:Column binding "Employee::CUSTOMERNUMBER" has referred to a data set column "Employee::CUSTOMERNUMBER" which is not exist.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/PreparedJointDataSourceQuery.java
* 
	 * @see org.eclipse.birt.data.engine.api.IPreparedQuery#getParameterMetaData()
	 */
	public Collection getParameterMetaData( ) throws BirtException
	{
		return null;
	}
	
	/**
	 * cache the left and right queryResults to improve the efficiency
	 * 
	 * @throws DataException
	 */
	private void populatePreparedQuery( ) throws DataException
	{
		this.leftQueryResults = populatePreparedQuery( true,
				PreparedJointDataSourceQuery.this.dataSet.getLeftDataSetDesignName( ) );
		this.rightQueryResults = populatePreparedQuery( false,
				PreparedJointDataSourceQuery.this.dataSet.getRightDataSetDesignName( ) );
	}
	/**
	 * 
	 * @param isLeftDataSet
	 * @param dataSetName
	 * @return
	 * @throws DataException
	 */
	private IQueryResults populatePreparedQuery( boolean isLeftDataSet, String dataSetName ) throws DataException
	{
		List conditions = PreparedJointDataSourceQuery.this.dataSet.getJoinConditions( );