View the list of available external columns in the data source. You cannot use this table to add or delete columns.
View external (source) columns in the order in which the task will read them. You can change this order by first clearing the selected columns in the table displayed in the editor, and then selecting external columns from the list in a different order.
Provide a unique name for each output column. The default is the name of the selected external (source) column; however, you can choose any unique, descriptive name. The name provided will be displayed within SSIS Designer.