CHAR vs GRAPHIC in DB2

db2 => describe table test

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
NAME                            SYSIBM    GRAPHIC                     10     0 Yes   

  1 record(s) selected.

db2 => describe table test1

                                Data type                     Column
Column name                     schema    Data type name      Length     Scale Nulls
------------------------------- --------- ------------------- ---------- ----- ------
NAME                            SYSIBM    CHARACTER                   10     0 Yes   

  1 record(s) selected.

如果插入英文字母，那麼都最多可以插入10個
db2 => insert into test values('helloworld')
DB20000I  The SQL command completed successfully.
db2 => insert into test1 values('helloworld')
DB20000I  The SQL command completed successfully.

插入漢字，最多可以插入幾個那？
db2 => insert into test values('插入十個漢字試試看吧')
DB20000I  The SQL command completed successfully.
db2 => insert into test1 values('插入十個漢字試試看吧')
DB21034E  The command was processed as an SQL statement because it was not a
valid Command Line Processor command.  During SQL processing it returned:
SQL0433N  Value "插入十個漢字試試看吧" is too long.  SQLSTATE=22001

GRAPHIC型別，那麼那個10就表示個數，無論是英文，漢字，日文，都是指的個數
CHAR型別定義的那個10表示的是位元組數，在UTF-8的編碼下，一個漢字佔用3個位元組
db2 => insert into test1 values('插入十g')
DB20000I  The SQL command completed successfully.
db2 => insert into test1 values('插入十gh')
DB21034E  The command was processed as an SQL statement because it was not a
valid Command Line Processor command.  During SQL processing it returned:
SQL0433N  Value "插入十gh" is too long.  SQLSTATE=22001

GRAPHIC型別有個好處，比如你用substr，你可以擷取到整個的字元，無論是什麼字元，都是整個的
但是CHAR型別，你很可能擷取到的字元是個亂碼