Use of TABLE_EXISTS_ACTION parameter in IMPDP
TABLE_EXISTS_ACTION = SKIP
Table_Exists_Action =Skip: skip is for skipping the table which are already exist in the database this is the default value for parameter table_exists_action.
TABLE_EXISTS_ACTION = APPEND
Table_Exists_Action =Append: append is for appending the data in tables which are already in the database .by using append new rows are inserted in tables and skipping already exist rows and for this number of columns and type of column matches.
TABLE_EXISTS_ACTION = TRUNCATE
Table_Exists_Action =Truncate: In this option if tables is already exist in the database then truncate that table and insert the data into existing table and not changing the definition.
TABLE_EXISTS_ACTION = REPLACE
Table_Exists_Action =Replace: replace is for replacing the data as well as the definition of existing table and it is basically for when table definitions are different in database from dmp file