File delimiters separate data-source fields. Outside rules files, data-source fields are delimited by spaces. Within rules files, by default, data-source fields are delimited by tabs.
Within data load or dimension build rules files, you can set commas, tabs, white spaces, fixed-width columns, or custom values as file delimiters. You need not set file delimiters for SQL data. File delimiters set for SQL data are ignored.
Select Options, then Data source properties.
In the Data Source Properties dialog box, select the Delimiter tab.
If you selected a custom file delimiter, in the text box, enter a character from the standard ASCII character set, from 0 to 127.
If you selected fixed-width columns, in the text box, enter the column width.