How change NLS_NCHAR_CHARACTERSET 

To check NLS_NCHAR_CHARACTERSET
column VALUE format a30
column PARAMETER format a30
select * from v$nls_parameters;


or 


select value$ 
from sys.props$ 
where name = 'NLS_CHARACTERSET';






step by step


note: must be take full backup






shutdown immediate






startup mount


alter system enable restricted session;


alter database open;


alter database character set WE8MSWIN1252;


startup


















































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