OracleÃÜÂëÎļþµÄ×÷ÓúÍ˵Ã÷
ÔÚÊý¾Ý¿âδÆô¶¯Ö®Ç°µÇ½´Ó¶øÆô¶¯Êý¾Ý¿âÈç¹ûûÓпÚÁîÎļþ£¬ÔÚÊý¾Ý¿âδÆô¶¯Ö®Ç°¾ÍÖ»ÄÜͨ¹ý²Ù×÷ϵͳÈÏÖ¤.ʹÓÃRman£¬ºÜ¶àʱºòÐèÒªÔÚnomount,mountµÈ״̬¶ÔÊý¾Ý¿â½øÐд¦Àí¡£ËùÒÔͨ³£ÒªÇósysdbaȨÏÞÈç¹ûÊôÓÚ±¾µØDBA×飬¿ÉÒÔͨ¹ý²Ù×÷ϵͳÈÏÖ¤µÇ½Èç¹ûÊÇÔ¶³ÌsysdbaµÇ½£¬ÐèҪͨ¹ýpasswordfileÈÏÖ¤¡£
1.remote_login_passwordfile = NONE
´ËʱͣÓÿÚÁîÎļþÑéÖ¤£¬OracleÊý¾Ý¿â²»ÔÊÐíÔ¶³ÌSYSDBA/SYSOPERÉí·ÝµÇ¼ÎÞ·¨Í¨¹ýÔ¶³Ì½øÐÐÊý¾Ý¿âÆðÍ£µÈ²Ù×÷¹ÜÀílocal:
[oracle@jumper oracle]$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.3.0 - Production on Thu Apr 15 09:58:45 2004
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.3.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.3.0 - Production
SQL> alter user sys identified by oracle;
User altered.
SQL> show parameter pass
NAME TYPE VALUE
--------------------- ----------- ------------------------------
remote_login_passwordfile string NONE
remote:
E:\Oracle\ora92\bin>sqlplus /nologSQL*Plus: Release 9.2.0.4.0 -
Production on ÐÇÆÚËÄ 4ÔÂ 15 09:39:22 2004Copyright (c) 1982, 2002, Oracle
Corporation. All rights reserved.SQL> connect sys/oracle@hsjf as
sysdbaERROR:ORA-01017: invalid username/password; logon denied
´Ë´¦Êµ¼ÊÉÏÊÇÎÞ·¨Í¨¹ý¿ÚÁîÎļþÑéÖ¤
2.remote_login_passwordfile = exclusive
SQL> alter system set remote_login_passwordfile=exclusive scope=spfile;
System altered.
SQL> startup force;
ORACLE instance started.
Total System Global Area 131142648 bytes
Fixed Size 451576 bytes
Variable Size 104857600 bytes
Database Buffers 25165824 bytes
Redo Buffers 667648 bytes
Database mounted.
Database opened.
SQL> show parameter pass
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
remote_login_passwordfile string EXCLUSIVE
SQL
Ïà¹ØÎĵµ£º
×÷Õߣº ÈÕÆÚ£º2005-12-8 1:43:32 À´Ô´£ºInternet µã»÷£º´Î ÆÀÂÛ
¡¡¡¡±¾ÎÄÖ»ÌÖÂÛOracleÖÐ×î³£¼ûµÄË÷Òý£¬¼´ÊÇB-treeË÷Òý¡£±¾ÎÄÖÐÉæ¼°µÄÊý¾Ý¿â°æ±¾ÊÇOracle8i¡£
¡¡¡¡Ò». ²é¿´ÏµÍ³±íÖеÄÓû§Ë÷Òý
¡¡¡¡ÔÚOracleÖУ¬SYSTEM±íÊǰ²×°Êý¾Ý¿âʱ×Ô¶¯½¨Á¢µÄ£¬Ëü°üº¬Êý¾Ý¿âµÄÈ«²¿Êý¾ ......
Oracle Process Structure
Oracle takes advantage of various types of processes:
¡¡—User process: Started at the time a database user requests connection to the Oracle server
—Server process: Connects to the Oracle instance and is started when a user establishes a session
& ......
select sysdate from dual; ´Óα±í²éϵͳʱ¼ä£¬ÒÔĬÈϸñʽÊä³ö¡£
sysdate+(5/24/60/60) ÔÚϵͳʱ¼ä»ù´¡ÉÏÑÓ³Ù5Ãë
sysdate+5/24/60 ÔÚϵͳʱ¼ä»ù´¡ÉÏÑÓ³Ù5·ÖÖÓ
sysdate+5/24 ÔÚϵͳʱ¼ä»ù´¡ÉÏÑÓ³Ù5Сʱ
sysdate+5 ÔÚϵͳʱ¼ä»ù´¡ÉÏÑÓ³Ù5Ìì
ËùÒÔÈÕÆÚ¼ÆËãĬÈϵ¥Î»ÊÇÌì
round (sysdate,’day’) ²»ÊÇËijý ......
¸Õ²ÅÔÚÍøÉÏËÑÕâ¸öÎÊÌâµÄʱºòËѵ½ITPUBÉÏyangtingkun²©¿ÍÀïµÄһƪÎÄÕ£¬Ð´µÄͦºÃµÄ£¬×Ô¼º¸´ÖÆÁËÒ»ÏÂËûµÄʵÑé¹ý³Ì£¬¼ÓÁ˵㲽ÖèÑéÖ¤ÁË×Ô¼ºµÄÏë·¨£¬Ò²½â¾öÁËÒÉÎÊ¡£
Ç°ÃæÐ´¹ýһƪÎÄÕ£¬½éÉܹýÎ¨Ò»Ô¼ÊøµÄÇé¿öÏ£¬Oracle´¦ÀíNULLµÄÌØµã¡£¼òµ¥µÄ˵£¬¾ÍÊÇÈç¹û¶à¸öÁй¹³ÉÁËΨһ£¬ÇÒÆäÖаüº¬Ò»¸öÒÔÉϵÄNULL£¬ÄÇôOracle»áÒªÇó²»ÎªNULL ......
ÔÚOracleÖпÉÒÔ´´½¨×éºÏË÷Òý£¬¼´Í¬Ê±°üº¬Á½¸ö»òÁ½¸öÒÔÉÏÁеÄË÷Òý¡£ÔÚ×éºÏË÷ÒýµÄʹÓ÷½Ã棬OracleÓÐÒÔÏÂÌØµã£º
1¡¢ µ±Ê¹ÓûùÓÚ¹æÔòµÄÓÅ»¯Æ÷£¨RBO£©Ê±£¬Ö»Óе±×éºÏË÷ÒýµÄǰµ¼ÁгöÏÖÔÚSQLÓï¾äµÄwhere×Ó¾äÖÐʱ£¬²Å»áʹÓõ½¸ÃË÷Òý£»
2¡¢ ÔÚʹÓÃOracle9i֮ǰµÄ»ùÓڳɱ¾µÄÓÅ»¯Æ÷£¨CBO£©Ê± ......