Bug 152430 Key can modify to empty string
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DataSetParameterHandle.java
{
	/**
	 * Constructs the handle of data set parameter.
	 * 
	 * @param valueHandle
	 *            the value handle for data set parameter list of one property
	 * @param index
	 *            the position of this data set parameter in the list
	 */
	public DataSetParameterHandle( SimpleValueHandle valueHandle, int index )
	{
		super( valueHandle, index );
	}
	/**
	 * Returns the data type of this parameter. The possible values are:
	 * 
	 * <ul>
	 * <li>COLUMN_DATA_TYPE_ANY
	 * <li>COLUMN_DATA_TYPE_INTEGER
	 * <li>COLUMN_DATA_TYPE_STRING