The Data | Edit | Delete Unlinked Data
command 
removes entire rows of data when they are
not used on the active thematic map. For example, you might have a data
file for an entire state in the worksheet but your thematic map only contains
half the counties for that state. When this occurs and you click the Data | Edit
| Delete Unlinked Data command, rows with primary IDs that do not
have corresponding linked areas on the map are eliminated from the data
file.
When multiple rows contain the same PID, only the first row (the row with the smallest Row Number) is linked to the object in the plot document. Multi-graph maps are an exception, as they contain XY data sets for each object. For all other map types, the Delete Unlinked Data command quickly removes duplicate PIDs and their associated data.
This command removes the rows of data from the worksheet. If the file is saved after the unlinked data is deleted, the deleted data is no longer contained in the worksheet. To preserve the original data, save the file to a new name with the File | Save As command immediately before deleting unlinked data.
See Also