ORA-31679: Table data object “Table_Name” has long columns, and longs can not be loaded/unloaded using a network link
ORA-31679 error occurs when we try to import the data using impdp over a network link.
When the remote database contains table data object that has long columns, and longs can not be loaded/unloaded using a network link.
To solve this you need to create a dump file on remote system using expdp and copy that dump file on your local system and import that dump file using impdp. This is little bit costly as it contains export, copy and import but this the only solution.