How To Find Database Character Set In Oracle

Database Character Set Healthcheck (Doc ID 225938.one)

Final updated on FEBRUARY 14, 2022

Applies to:

Oracle Database - Standard Edition - Version viii.1.7.four and subsequently
Oracle Database - Enterprise Edition - Version 8.one.seven.4 and later
Oracle Database Cloud Schema Service - Version Due north/A and later
Oracle Database Exadata Cloud Auto - Version North/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this certificate applies to whatever platform. ***   ***

Purpose

To give a overview of things you can cheque to debug "Lossy" data in a csscan output or to deduct what kind of encodings you have (incorrectly) stored in your database.

Scope

WARNINGS

a) This is a rather "skillful" level note. Please do NOT overrate your skills. If things are not articulate, please log a SR, refer to this notation and ask that someone from the RDBMS NLS "advanced resolution squad" reviews your problem.

b) This notation is the LAST step in debugging "display problems" like "I can't insert <your special character here> in a database". The FIRST step when having problem inserting NEW data is to come across if your CURRENT database NLS_CHARACTERSET supports the character you want to insert.
The electric current NLS_CHARACTERSET is seen in NLS_DATABASE_PARAMETERS.

A very easy fashion to see if your electric current NLS_CHARACTERSET supports/defines the grapheme y'all endeavor to insert is to utilize an Unicode customer like Oracle SQL Developer.
<note 1628060.i> How to diagnose losing characters , getting "funny" output when inserting or selecting other than A-Z,a-z data ( = non English language information like Chinese, Russian, Hebrew , insert any language here to the list that is non English) CHAR, VARCHAR2, LONG or CLOB

Please starting time in to a higher place note to debug the problem.

c) If EXISTING data is NOT showing upwards correctly then check starting time if you can insert NEW information in a test table using SQLdeveloper. If this is possible and then your current NLS_CHARTERSET defines this and EXISTING information cannot be seen in Sqldeveloper then you have (some) "garbage" data in your database and you can utilize this flow to effort to rescue that information and AFTER that you can right the "insert" (application) side.
If NEW and EXISITING information cannot be seen correctly seen in Sqldeveloper then this means the current NLS_CHARTERSET does Non define this language and you can utilize this period to right the NLS_CHARACTERSET.

d) If following this flowchart is taking you lot further and then step ii you CANNOT go directly to another character set, even AL32UTF8. Offset the current *wrong* setup needs to be corrected even if this means going starting time to an other character gear up.

eastward) If you are following this note because after a migration to a new version *without* changing the NLS_CHARACTERSET you have problems with some characters then please follow this note using you Former NLS situation (=the NLS_LANG used on old clients before the migration to the new version of Oracle)

f) If post-obit this note results in changing a database running on a Unix arrangement to a "MSWIN" characterset and so this is Not a trouble. You can apply on Unix an database with a "Windows" characterset like WE8MSWIN1252. The only restriction is that yous cannot apply EBCDIC charactersets (similar used on AS400 ea) on ASCII based platforms (like used on Unix and Windows) (or changed) for the database characterset.

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Source: https://support.oracle.com/knowledge/Oracle%20Database%20Products/225938_1.html

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