# Mapping Fields

Once the correct record has been selected, it must be updated or created.

The mapping table specifies how the source fields are mapped to the target table. To do the mapping, simply select the source field in the left hand column, and the target field in the right hand column.

If you have a professional license, you can also specify two further options, on a field by field basis:

1. Skip if source blank - this means that if the source field is blank, it will not be written to the target field. This is useful when updating; it ensures that blanks do not overwrite possibly valid data in the target.
2. Skip if target not blank - this is a stronger version of (1); it means that if the target field has any data at all, it will not be overwritten by the source field. Essentially this is saying "the target is master - only bring in source data if target has nothing".