Online Documentation for Data Pump for Oracle
Global type mapping
In this dialog you can view and edit the type conversion grid where the correspondence between the data types of the OLE DB Provider being used and the target database server (i.e. Oracle) data types is displayed. You can use this grid to set conversion preferences for each of the types.
The Data type editor dialog can be opened by clicking the ellipsis 
button to the right of the record to be edited.
In the Data type editor dialog you can specify whether the source field type returned by the OLE DB Provider is to be converted to a data type of the target database server (i.e. Oracle).
For certain data types you can set scale, size and/or precision.
