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Character set vs National Character set [message #291731] Sun, 06 January 2008 05:37 Go to next message
ibnadam
Messages: 7
Registered: December 2007
Junior Member
Hi experts,


I have a very basic question regarding character set.
I would like to explain you all what i have understood of these
words.

Character set: It is the character set of the database.
National character set: It is alternative to the character set, if any character is not available in character set it is used from national character set. am I correct?

Q. If i am using unicode as my database character set what is the need to use national character set since it is universal character set which handle almost all languages like eg: arabic and english atleast

Suppose if i want to store arabic and english data in my database. I would take unicode as my character set and i will ignore national character set. am i correct.

Please tell me what is the actual difference between national character set vs character set of the database.

Thank very much,

Regards.
Re: Character set vs National Character set [message #291742 is a reply to message #291731] Sun, 06 January 2008 09:14 Go to previous messageGo to next message
Michel Cadot
Messages: 64130
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Quote:

National character set: It is alternative to the character set

Yes
Quote:

if any character is not available in character set it is used from national character set. am I correct?

National character set is used in NCHAR, NVARCHAR2, NCLOB columns. You use these datatypes when you have data that does not fit in your database character set and you want to record them IN SPECIAL COLUMNS.

Quote:

If i am using unicode as my database character set what is the need to use national character set

There is no need.
National character set is here for backward compatibility and was useful when unicode did not exist.

Regards
Michel
Re: Character set vs National Character set [message #291788 is a reply to message #291742] Sun, 06 January 2008 22:46 Go to previous messageGo to next message
ibnadam
Messages: 7
Registered: December 2007
Junior Member
Thanks very much Michel,

I get it,but

Quote:

There is no need.
National character set is here for backward compatibility and was useful when unicode did not exist.




But if I use dbca to create any new database taking unicode as character set ,it takes national character set as AL16UTF16 OR UTF8 by default even in 9i or 10g.

And if i export from a database which uses arabic and english boht the languages, i get following message.

Export file created by EXPORT:V08.00.05 via conventional path
import done in AR8ISO8859P6 character set and AL16UTF16 NCHAR character set
export server uses AR8ISO8859P6 NCHAR character set (possible ncharset conversion)


I fear whether my data get corrupted if i don't use the same character set combination and i use unicode at target database.

The above code is taken from 9i export utility , you can see here in this code also we have nchar as AL16UTF16.
I am very confused even when i am taking export, because we need to take care of character set.

Please clarify, and excuse me if it is not put in a proper way.

[Updated on: Sun, 06 January 2008 22:47]

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Re: Character set vs National Character set [message #291805 is a reply to message #291788] Sun, 06 January 2008 23:50 Go to previous message
Michel Cadot
Messages: 64130
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
It only matters if you use N<something> datatype.
But as AL16UTF16 contains all characters and so include AR8ISO8859P6 ones you don't have to worry.

Regards
Michel

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