Bug 156166 Error occour when previewing attached report in web viewer.
Decription:Error occour when previewing attached report in web viewer. Steps to reproduce: 1.run attached reports in web viewer. Expeceted results: preview properly Actual results: Error occour when previewing the reports in web viewer while it works properly in html and PDF
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/BindingColumnsEvalUtil.java
{
		
		private String columnName;
		private IBaseExpression baseExpr;
		private BindingColumn( String columnName, IBaseExpression baseExpr )
		{
			this.columnName = columnName;
			this.baseExpr = baseExpr;
		}
	}
	
	/**
	 * Special case for query running based on report document. A life cycle
	 * might be below:
	 * 
	 * 1: create an original report design
	 * 
	 * 2: running this design and save the result into a report document
	 * 
	 * 3: only modify the transformation of the report design 1 and continue
	 * running the new report design based on the report document of step 2
	 * 
	 * 4: the column binding of the original report design can also used in the
	 * new query result of step 3
	 */
	private class EvalHelper