含有汉字的固定字符由ZHS16GBK数据库导入到AL32UTF8的数据库

导读：
此文章是对于上一个实验的补充，上一次实验仅仅考虑的 varchar2 的情况。这次考虑到对于char类型的含有中文数据的情况。
对于英文：
对英文，在al32utf8中仍然和zhs16gbk一样用1个字节表示，因此导入固定长度英文字符数据时不会出错。
对于中文：
例如在字符集为zhs16gbk 数据库中创建表时指定字段 val char（15），该字段含有数据 ‘阿里云计算公司’在字符集为zhs16gbk 数据库中占用14个字

节，而在字符集为al32utf8 数据库中占用21个字节 大于 char（15）所指定的长度15.此时导入数据就会失败。
下面对于上述情况给以说明。
=======================迁移 英文固定长度字符数据====================
=======================创建表，含有英文固定长度字符数据=============
yang@ORACL> create table fixed_char ( val char(15) );
表已创建。
yang@ORACL> insert into fixed_char select
  2  dbms_random.string('l',15) from dual
  3  connect by level <125;
已创建124行。
yang@ORACL> select val from fixed_char;
VAL
---------------
oxmjgwgzbjhthcr
elbdlcpkfajsmrc
jrwccslaywxpiwj
...............
ljkowkocmdqnkgj
idialvaxohrahah
zwrqynvtevfujao
funkxaokotsblww
snyetpafaneicjm
kgrcrpbwlvtotcv
knhcazjkgotzvmg
myqgvjqnsingmxv
klthqehltsyzrxe
voucbpykpnsbopx
vtvavjddyafwqxt
omcnkpvlhlxdvvg
ccfpttivbdvursz
已选择124行。
yang@ORACL> spool d:\fixed_char.txt
yang@ORACL> insert into fixed_char select
  2  dbms_random.string('l',15) from dual
  3  connect by level <125;
已创建124行。
yang@ORACL> select val from fixed_char where rownum <10;
VAL
---------------
oxmjgwgzbjhthcr
elbdlcpkfajsmrc
jrwccslaywxpiwj
clizpikggppgfwy
yqqxljlscqaiqli
lrwoayaxyjzgdhy
rkqpujyupltmrqb
qvycepfgtwipwat
iccsgvrpfxwligq
已选择9行。
yang@ORACL> commit;
提交完成。
=========================导出数据================================
C:\Users\aaaa>expdp yang/yang tables=fixed_char directory=dumpdir dumpfile=fixed_char_zhs16gbk.dmp l
ogfile=fixed_char.log
Export: Release 11.1.0.6.0 - Production on 星期六, 12 3月, 2011 12:25:55
Copyright (c) 2003, 2007, Oracle.  All rights reserved.
连接到: Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
启动 "YANG"."SYS_EXPORT_TABLE_01":  yang/******** tables=fixed_char directory=dumpdir dumpfile=fixed
_char_zhs16gbk.dmp logfile=fixed_char.log
正在使用 BLOCKS 方法进行估计...
处理对象类型 TABLE_EXPORT/TABLE/TABLE_DATA
使用 BLOCKS 方法的总估计: 64 KB
处理对象类型 TABLE_EXPORT/TABLE/TABLE
. . 导出了 "YANG"."FIXED_CHAR"                         9.851 KB     248 行
已成功加载/卸载了主表 "YANG"."SYS_EXPORT_TABLE_01"
******************************************************************************
YANG.SYS_EXPORT_TABLE_01 的转储文件集为:
  D:\DUMP\FIXED_CHAR_ZHS16GBK.DMP
作业 "YANG"."SYS_EXPORT_TABLE_01" 已于 12:27:32 成功完成
=====================================导入数据=============================================
oracle@rac1:rac1 /tmp/dump>impdp yang/yang tables=fixed_char directory=dumpdir dumpfile=fixed_char_zhs16gbk.dmp

log=fixedchar_zhs16gbk_to_al32utf8.log
Import: Release 11.2.0.1.0 - Production on Sat Mar 12 12:31:34 2011
Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
Legacy Mode Active due to the following parameters:
Legacy Mode Parameter: "log=fixedchar_zhs16gbk_to_al32utf8.log" Location: Command Line, Replaced with:

"logfile=fixedchar_zhs16gbk_to_al32utf8.log"
Master table "YANG"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "YANG"."SYS_IMPORT_TABLE_01":  yang/******** tables=fixed_char directory=dumpdir dumpfile=fixed_char_zhs16gbk.dmp

logfile=fixedchar_zhs16gbk_to_al32utf8.log
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "YANG"."FIXED_CHAR"                         9.851 KB     248 rows
Job "YANG"."SYS_IMPORT_TABLE_01" successfully completed at 12:31:38
==================================在目标库里验证数据====================================
yang@rac1>select table_name from user_tables;
TABLE_NAME
------------------------------
CHARSET
CHART
TCHAR
FIXED_CHAR
yang@rac1>desc fixed_char
Name                     Null?    Type
----------------------- -------- -------
VAL                              CHAR(15)
yang@rac1>select val from fixed_char where rownum <12;
VAL
---------------
oxmjgwgzbjhthcr
elbdlcpkfajsmrc
jrwccslaywxpiwj
clizpikggppgfwy
yqqxljlscqaiqli
lrwoayaxyjzgdhy
rkqpujyupltmrqb
qvycepfgtwipwat
iccsgvrpfxwligq
zrtwmeviosnsgmv
chwsezhjfgnsjll
11 rows selected.
yang@rac1>select dump(val) from fixed_char where rownum <10;
DUMP(VAL)
--------------------------------------------------------------------------
Typ=96 Len=15: 111,120,109,106,103,119,103,122,98,106,104,116,104,99,114
Typ=96 Len=15: 101,108,98,100,108,99,112,107,102,97,106,115,109,114,99
Typ=96 Len=15: 106,114,119,99,99,115,108,97,121,119,120,112,105,119,106
Typ=96 Len=15: 99,108,105,122,112,105,107,103,103,112,112,103,102,119,121
Typ=96 Len=15: 121,113,113,120,108,106,108,115,99,113,97,105,113,108,105
Typ=96 Len=15: 108,114,119,111,97,121,97,120,121,106,122,103,100,104,121
Typ=96 Len=15: 114,107,113,112,117,106,121,117,112,108,116,109,114,113,98
Typ=96 Len=15: 113,118,121,99,101,112,102,103,116,119,105,112,119,97,116
Typ=96 Len=15: 105,99,99,115,103,118,114,112,102,120,119,108,105,103,113
9 rows selected.
对于英文字符可以实现由zhs16gbk 到 al32utf8的转换。
解释：用UTF-8，UNICODE的2字节字符用变长个（1－3个字节）表示：
1. 对英文，仍然和ASCII一样用1个字节表示，这个字节的值小于128(\x80)；
2. 扩展的ASCII字符（主要是西欧），第一字节用C2 - DF之间的范围，双字节表示。
3.对其他语言，比如亚洲语系，还有各种特殊符号，使用3个字节表示；
因此，在应用中程序处理过程中所有字符都是16位（双字节），但在存取转换成字节流时使用UTF-8格式转换，对于英文字符来说和原来用ASCII方式存取

时相比大小仍然是一样的，而对中文来说和原来的GB2312编码方式相比，大小为：(3字节/2字节)=1.5倍，这也是下面导入数据失败的原因。
==================================迁移含有汉字 固定字符数据=============================
=====================创建表，含有汉字的固定字符数据======================================
yang@ORACL> create table fixed( val1 char(15),val2 char(15) );
表已创建。
yang@ORACL> insert into fixed select
  2  dbms_random.string('l',15) val1,
  3  '阿里云算公司' as val2
  4  from dual
  5  connect by level <500;
已创建499行。
yang@ORACL> select dump('阿里云计算公司') from dual;
DUMP('阿里云计算公司')
----------------------------------------------------------------------
Typ=96 Len=14: 176,162,192,239,212,198,188,198,203,227,185,171,203,190
yang@ORACL> commit;
提交完成。
yang@ORACL> select count(*) from fixed;
  COUNT(*)
----------
       499
yang@ORACL>
========================导出操作===========================================
C:\Users\aaaa>expdp yang/yang tables=fixed directory=dumpdir dumpfile=fixed_zhs16gbk.dmp logfile=fixed.log
Export: Release 11.1.0.6.0 - Production on 星期六, 12 3月, 2011 12:50:05
Copyright (c) 2003, 2007, Oracle.  All rights reserved.
连接到: Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
启动 "YANG"."SYS_EXPORT_TABLE_01":  yang/******** tables=fixed directory=dumpdir dumpfile=fixed_zhs1
6gbk.dmp logfile=fixed.log
正在使用 BLOCKS 方法进行估计...
处理对象类型 TABLE_EXPORT/TABLE/TABLE_DATA
使用 BLOCKS 方法的总估计: 64 KB
处理对象类型 TABLE_EXPORT/TABLE/TABLE
. . 导出了 "YANG"."FIXED"                              22.94 KB     499 行
已成功加载/卸载了主表 "YANG"."SYS_EXPORT_TABLE_01"
******************************************************************************
YANG.SYS_EXPORT_TABLE_01 的转储文件集为:
  D:\DUMP\FIXED_ZHS16GBK.DMP
作业 "YANG"."SYS_EXPORT_TABLE_01" 已于 12:50:53 成功完成
C:\Users\aaaa>
========================导入操作=====================================================================
oracle@rac1:rac1 /tmp/dump>impdp yang/yang tables=fixed directory=dumpdir dumpfile=fixed_zhs16gbk.dmp

log=fixed_zhs16gbk_to_al32utf8.log
Import: Release 11.2.0.1.0 - Production on Sat Mar 12 12:52:38 2011
Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
Legacy Mode Active due to the following parameters:
Legacy Mode Parameter: "log=fixed_zhs16gbk_to_al32utf8.log" Location: Command Line, Replaced with:

"logfile=fixed_zhs16gbk_to_al32utf8.log"
Master table "YANG"."SYS_IMPORT_TABLE_01" successfully loaded/unloaded
Starting "YANG"."SYS_IMPORT_TABLE_01":  yang/******** tables=fixed directory=dumpdir dumpfile=fixed_zhs16gbk.dmp

logfile=fixed_zhs16gbk_to_al32utf8.log
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
ORA-02374: conversion error loading table "YANG"."FIXED"
ORA-12899: value too large for column VAL2 (actual: 21, maximum: 15)===> 需要21个字节但是 char(15）规定val2字段长度是15
ORA-02372: data for row: VAL2 : 0X'B0A2C0EFD4C6CBE3B9ABCBBE202020'
ORA-02374: conversion error loading table "YANG"."FIXED"
ORA-12899: value too large for column VAL2 (actual: 21, maximum: 15)
ORA-02372: data for row: VAL2 : 0X'B0A2C0EFD4C6CBE3B9ABCBBE202020'
ORA-02374: conversion error loading table "YANG"."FIXED"
ORA-12899: value too large for column VAL2 (actual: 21, maximum: 15)
ORA-02372: data for row: VAL2 : 0X'B0A2C0EFD4C6CBE3B9ABCBBE202020'
ORA-02374: conversion error loading table "YANG"."FIXED"
ORA-12899: value too large for column VAL2 (actual: 21, maximum: 15)
ORA-02372: data for row: VAL2 : 0X'B0A2C0EFD4C6CBE3B9ABCBBE202020'
ORA-02374: conversion error loading table "YANG"."FIXED"
ORA-12899: value too large for column VAL2 (actual: 21, maximum: 15)