Oracle export/import and Character Set Information viewing

Oracle export/import and Character Set Information viewing for data import and export, we should pay attention to the character set issue. In the EXP/IMP process, we need to pay attention to the four character set parameters: the client character set at the export end, the database character set at the export end, the client character set at the import end, and the database character set at the import end. First, we need to view the parameters of these four character sets. View information about the character set of the database: SQL> select * from nation; PARAMETER VALUE contains invalid NLS_LANGUAGE AMERICAN NLS_TERRITORY AMERICA NLS_CURRENCY $ sort AMERICA nation., please ZHS16GBK NLS_CALENDAR GREGORIAN NLS_DATE_FORMAT DD-MON-RR NLS_DATE_LANGUAGE AMERICAN NL S_SORT BINARY NLS_TIME_FORMAT HH. MI. ssxff am NLS_TIMESTAMP_FORMAT DD-MON-RR HH. MI. ssxff am NLS_TIME_TZ_FORMAT HH. MI. ssxff am tzh: TZM NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH. MI. ssxff am tzh: TZM NLS_DUAL_CURRENCY $ NLS_COMP BINARY NLS_NCHAR_CHARACTERSET ZHS16GBK NLS_RDBMS_VERSION 8.1.7.4.1 NLS_CHARACTERSET: ZHS16GBK is the character set of the current database. Let's look at the character set information of the client: the client Character Set parameter NLS_LANG =_< territory>. language: Specifies the language in which oracle messages are displayed, including the date, day, And month. Territory: Specifies the format of currency and number, region and the habit of calculating the week and date. Characterset: controls the character set used by client applications. Usually set or equal to the client's code page. Or set the unicode application to UTF8. In windows, you can query and modify NLS_LANG in the registry. HKEY_LOCAL_MACHINE \ SOFTWARE \ Oracle \ HOMExx \ xx indicates the system number when multiple Oracle_HOME exists. In unix: $ env | grep NLS_LANG = simplified chinese_china.ZHS16GBK modification available: $ export NLS_LANG = AMERICAN_AMERICA.UTF8 it is best to set the client character set to the same as the database during export. When importing data, there are two main situations: (1) the source database and the target database have the same character set settings. In this case, you only need to set the Export and Import client NLS_LANG to be equal to the database character set. (2) The character sets of the source and target databases are different. First, set the export client's NLS_LANG to be consistent with the export database character set, export data, and then set the import client's NLS_LANG to be consistent with the export client, import data, in this way, the conversion only occurs on the Database End and only occurs once. In this case, data can be completely imported only when the character set of the importing database is a strict superset of the character set of the exporting database. Otherwise, data inconsistency or garbled characters may occur.