Check the Oracle DBMS Character Set
To check the character set of the Oracle DBMS, issue one of the following SQL queries using sqlplus or the Ingres SQL Terminal Monitor (isql) utility:
select value from v$nls_parameters where PARAMETER = 'NLS_CHARACTERSET';
select value from nls_session_parameters where PARAMETER = 'NLS_CHARACTERSET';
select value from SYS.NLS_DATABASE_PARAMETERS where PARAMETER = 'NLS_CHARACTERSET'
Note: Oracle's Character Set Scanner (CSSCAN) utility helps you determine the impact and feasibility of migrating character data in an Oracle database to a new character set.