SELECT value$ FROM sys.props$ WHERE name = 'NLS_CHARACTERSET' ; SELECT * FROM NLS_DATABASE_PARAMETERS select owner, table_name, column_name from dba_tab_columns where (data_type = 'NCHAR' or data_type = 'NVARCHAR2' or data_type = 'NCLOB') and owner != 'SYS' and owner != 'SYSTEM';