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Oracle»Ö復ÒâÍâ刪³ýµÄ數據

 1. flashback table table_test to timestamp to_timestamp('20091103000000','yyyymmddhh24miss');
 2.Èç¹û報錯ORA-08189: cannot flashback the table because row movement is not enabled
 3.alter table table_test enable row movement;
 4.OK


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oracleÖе¥¼Ç¼º¯ÊýµÄ¹éÄÉ×ܽá

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1.ASCII
·µ»ØÓëÖ¸¶¨µÄ×Ö·û¶ÔÓ¦µÄÊ®½øÖÆÊý;
SQL> select ascii(’A’) A,ascii(’a’) a,ascii(’0’) zero,ascii(’ ’) space from dual;
A A ZERO SPACE
--------- --------- --------- ---------
65 97 48 32
......

Oracle ²ÎÊýÎļþ×ܽá

1:pfileºÍspfile
ÔÚ9i֮ǰ£¬²ÎÊýÎļþÖ»ÓÐÒ»ÖÖ£¬ËüÊÇÎı¾¸ñʽµÄ£¬³ÆÎªpfile£¬ÔÚ9i¼°ÒÔºóµÄ°æ±¾ÖУ¬ÐÂÔöÁË·þÎñÆ÷²ÎÊýÎļþ,³ÆÎªspfile,ËüÊǶþ½øÖƸñʽµÄ¡£ÕâÁ½ÖÖ²ÎÊýÎļþ¶¼ÊÇÓÃÀ´´æ´¢²Î ÊýÅäÖÃÒÔ¹©oracle¶ÁÈ¡µÄ£¬µ«Ò²Óв»Í¬µã£¬×¢ÒâÒÔϼ¸µã£º
1)pfileÊÇÎı¾Îļþ£¬spfileÊǶþ½øÖÆÎļþ£»
2)¶ÔÓÚ²ÎÊýµÄÅäÖã¬pfile¿ÉÒÔÖ±½ÓÒÔÎ ......

OracleÖÐUSERENVºÍSYS_CONTEXT×ܽá[ת]

 
OracleÖÐUSERENVºÍSYS_CONTEXTÓÃÀ´·µ»Øµ±Ç°sessionµÄÐÅÏ¢£¬ÆäÖУ¬userenvÊÇΪÁ˱£³ÖÏòϼæÈݵÄÒÅÁôº¯Êý£¬ÍƼöʹÓÃsys_contextº¯Êýµ÷ÓÃuserenvÃüÃû¿Õ¼äÀ´»ñÈ¡Ïà¹ØÐÅÏ¢¡£
1¡¢ USERENV(OPTION)
¡¡¡¡·µ»Øµ±Ç°µÄ»á»°ÐÅÏ¢.
¡¡¡¡OPTION='ISDBA'Èôµ±Ç°ÊÇDBA½ÇÉ«,ÔòΪTRUE,·ñÔòFALSE.
¡¡¡¡OPTION='LANGUAGE'·µ»ØÊý¾Ý¿âµÄ ......

Oracle×Ö·û´®º¯Êý

 1.ASCII 
·µ»ØÓëÖ¸¶¨µÄ×Ö·û¶ÔÓ¦µÄÊ®½øÖÆÊý; 
SQL> select ascii(’A’) A,ascii(’a’) a,ascii(’0’) zero,ascii(’ ’) space from dual; 
A A ZERO SPACE 
--------- --------- --------- --------- 
65 97 48 32
2.CHR 
¸ø³öÕ ......
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