EXP-00056和 ORA-12154

EXP-00056: ORACLE error 12154 encountered
ORA-12154: TNS:could not resolve service name
EXP-00000: Export terminated unsuccessfully

Cause:

The import or export cannot find the net service name to connect to the
database.

Import and export connect to the database with the connect information
(userid, password, and net service name) that the RAU used to connect. The
net service name used by the RAU is in the tnsnames.ora file in the Designer
Oracle home (unless a TNS_ADMIN registry variable is defined for the Designer
Oracle home).