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Thread: Export/import

  1. #1
    Join Date
    Dec 2001
    Location
    Baltimore, MD
    Posts
    374

    Export/import

    Hi All
    What's the best way or how to handle an export/import with different character set?

    Here is the situation.

    Export was taking with UTF8 character set
    and is to be imported into a database with
    WE8ISO8859P1 character set.

    Please advise
    Thanks
    Last edited by Ablakios; 03-25-2003 at 07:52 PM.
    Arsene Lupain
    The lie takes the elevator, the truth takes the staircase but ends up catching up with the lie.

  2. #2
    Join Date
    Nov 2002
    Location
    New Delhi, INDIA
    Posts
    1,796
    During an import the data is automatcally converted to session character set specified by NLS_LANG parameter. Then it is converted to the database character set. This means that the NLS_LANG must specify the character set of the export dump file.

    When data is converted, the target characterset must contain a representation of all characters that exist in the data.

    Example
    Your source database has character set A and you use a client session which has character set (NLS_LANG) B. Then a character set conversion may occur and the dumpfile will have data with character set B.

    Now at the import site your client has character set C and the database has character set D. Then while import the character set conversion may occur from character set B to c and then finally to D.
    In the above example i have used character set conversion may occur. This is because if the character set to which data is moving is a superset of the preceding character set or has all the characters defined at the right location then the conversion will not occur.

    There should not be any problem of moving from a UTF8 to WE8ISO8859P1 as they are both considered supersets
    Last edited by adewri; 03-26-2003 at 01:50 AM.
    Amar
    "There is a difference between knowing the path and walking the path."

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  3. #3
    Join Date
    Aug 2000
    Location
    Shanghai
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    433
    what happen if I export a tranditional chinese character set export and import to a simplific chinese character set database . An error occuries .
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  4. #4
    Join Date
    May 2001
    Posts
    736
    As explained by Amar
    ---------------------------------------
    Your source database has character set A and you use a client session which has character set (NLS_LANG) B. Then a character set conversion may occur and the dumpfile will have data with character set B.

    Now at the import site your client has character set C and the database has character set D. Then while import the character set conversion may occur from character set B to c and then finally to D.

    ------------------------------------------
    This is fine when the session character set and datbase character set are superset.The real problem occurs when they are not superset.Even though import will not fail as system still try to convert the character set.But there will not any guarantee that the data will be consistent.

    Say for ex:your database character set is ARABIC and will take export with WE8ISO8859p1 since they are not super set still character set conversion will takesplace but your ARABIC data will be garbage.So when u are dealing with different character sets u have to be very careful.

    regards
    akhadar

  5. #5
    Join Date
    Dec 2001
    Location
    Baltimore, MD
    Posts
    374
    Thanks to all
    Arsene Lupain
    The lie takes the elevator, the truth takes the staircase but ends up catching up with the lie.

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