Bug 152430 Key can modify to empty string
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ResultSetColumnHandle.java
*            the column name to set
	 */
	public void setColumnName( String columnName )
	{
		setPropertySilently( ResultSetColumn.NAME_MEMBER, columnName );
	}
	/**
	 * Returns the data type of this column. The possible values are defined in
	 * {@link org.eclipse.birt.report.model.api.elements.DesignChoiceConstants},
	 * and they are:
	 * <ul>
	 * <li>COLUMN_DATA_TYPE_ANY
	 * <li>COLUMN_DATA_TYPE_INTEGER
	 * <li>COLUMN_DATA_TYPE_STRING
	 * <li>COLUMN_DATA_TYPE_DATETIME
	 * <li>COLUMN_DATA_TYPE_DECIMAL
	 * <li>COLUMN_DATA_TYPE_FLOAT
	 * <li>COLUMN_DATA_TYPE_STRUCTURE
	 * <li>COLUMN_DATA_TYPE_TABLE
	 * </ul>
	 * 
	 * @return the data type of this column.
	 */
	public String getDataType( )
	{
		return getStringProperty( ResultSetColumn.DATA_TYPE_MEMBER );
	}
	/**
	 * Sets the data type of this column. The allowed values are defined in
	 * {@link org.eclipse.birt.report.model.api.elements.DesignChoiceConstants},