My Oracle Support Banner

The National Character Set ( NLS_NCHAR_CHARACTERSET ) in Oracle 9i, 10g , 11g and 12c (Doc ID 276914.1)

Last updated on AUGUST 24, 2021

Applies to:

Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Database - Enterprise Edition - Version and later
Information in this document applies to any platform.


This Document provide all the details for National Character Set ( NLS_NCHAR_CHARACTERSET ) in Oracle 9i and up.


This bulletin provides the Database Administrator a better understanding of National Character Set .


To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!

In this Document
 1) What is the National Character Set?
 2) Which datatypes use the National Character Set?
 3) How to know if I use N-type columns?
 4) Should I worry when I upgrade from 8i or lower to 9i, 10g or 11g?
 5) The NLS_NCHAR_CHARACTERSET is NOT changed to UTF8 or AL16UTF16 after upgrading to 9i , 10g (or later).
 6) Can I change the AL16UTF16 to UTF8 / I hear that there are problems with AL16UTF16.
 7) Is the AL32UTF8 problem the same as the AL16UTF16 / do I need the same patches?
 8) But I still want <characterset> as NLS_NCHAR_CHARACTERSET, like I had in 8(i)!
 9) Do i need to set NLS_LANG to AL16UTF16 when creating/using the NLS_NCHAR_CHARACTERSET ?
 10) I try to use AL32UTF8 as NLS_NCHAR_CHARACTERSET but it fails with ORA-12714
 11) I have the message "( possible ncharset conversion )" during import.
 12) Can i use AL16UTF16 as NLS_CHARACTERSET ?
 13) I'm inserting <special character> in a Nchar or Nvarchar2 col but it comes back as ?, � or without accents when selected.
 14) Do i need to change the NLS_NCHAR_CHARACTERSET in 8i to UTF8 BEFORE upgrading to 9i/10g?
 15) Having an UTF8 or AL32UTF8 NLS_CHARACTERSET db is there a advantage to use AL16UTF16 N-types ?
 16) I have a message running DBUA (Database Upgrade Assistant) about NCHAR type when upgrading from 8i .
 18) What is the NLS_SAVED_NCHAR_CS characterset seen in some databases?
 19) Can I load data into Nchar, Nvarchar2 or Nclob using sqlldr or use external tables using N-types?
 20) Known issues

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.