Mysql£¬SqlServer£¬OracleÖ÷¼ü×Ô¶¯Ôö³¤µÄÉèÖÃ
Mysql£¬SqlServer£¬OracleÖ÷¼ü×Ô¶¯Ôö³¤µÄÉèÖÃ
1¡¢°ÑÖ÷¼ü¶¨ÒåΪ×Ô¶¯Ôö³¤±êʶ·ûÀàÐÍ
ÔÚmysqlÖУ¬Èç¹û°Ñ±íµÄÖ÷¼üÉèΪauto_incrementÀàÐÍ£¬Êý¾Ý¿â¾Í»á×Ô¶¯ÎªÖ÷¼ü¸³Öµ¡£ÀýÈ磺
create table customers(id int auto_increment primary key not null, name varchar(15));
insert into customers(name) values("name1"),("name2");
select id from customers;
ÒÔÉÏsqlÓï¾äÏÈ´´½¨ÁËcustomers±í£¬È»ºó²åÈëÁ½Ìõ¼Ç¼£¬ÔÚ²åÈëʱ½ö½öÉ趨ÁËname×ֶεÄÖµ¡£×îºó²éѯ±íÖÐid×ֶΣ¬²éѯ½á¹ûΪ£º
id
1
2
Óɴ˿ɼû£¬Ò»µ©°ÑidÉèΪauto_incrementÀàÐÍ£¬mysqlÊý¾Ý¿â»á×Ô¶¯°´µÝÔöµÄ·½Ê½ÎªÖ÷¼ü¸³Öµ¡£
ÔÚMS SQLServerÖУ¬Èç¹û°Ñ±íµÄÖ÷¼üÉèΪidentityÀàÐÍ£¬Êý¾Ý¿â¾Í»á×Ô¶¯ÎªÖ÷¼ü¸³Öµ¡£ÀýÈ磺
create table customers(id int identity(1,1) primary key not null, name varchar(15));
insert into customers(name) values("name1"),("name2");
select id from customers;
²éѯ½á¹ûºÍmysqlµÄÒ»Ñù¡£Óɴ˿ɼû£¬Ò»µ©°ÑidÉèΪidentityÀàÐÍ£¬MS SQLServerÊý¾Ý¿â»á×Ô¶¯°´µÝÔöµÄ·½Ê½ÎªÖ÷¼ü¸³Öµ¡£identity°üº¬Á½¸ö²ÎÊý£¬µÚÒ»¸ö²ÎÊý±íʾÆðʼֵ£¬µÚ¶þ¸ö²ÎÊý±íʾÔöÁ¿¡£
2¡¢´ÓÐòÁÐÖлñÈ¡×Ô¶¯Ôö³¤µÄ±êʶ·û
ÔÚOracleÖУ¬¿ÉÒÔΪÿÕűíµÄÖ÷¼ü´´½¨Ò»¸öµ¥¶ÀµÄÐòÁУ¬È»ºó´ÓÕâ¸öÐòÁÐÖлñÈ¡×Ô¶¯Ôö¼ÓµÄ±êʶ·û£¬°ÑËü¸³Öµ¸øÖ÷¼ü¡£ÀýÈçÒ»ÏÂÓï¾ä´´½¨ÁËÒ»¸öÃûΪcustomer_id_seqµÄÐòÁУ¬Õâ¸öÐòÁÐµÄÆðʼֵΪ1£¬ÔöÁ¿Îª2¡£
create sequence customer_id_seq increment by 2 start with 1
Ò»µ©¶¨ÒåÁËcustomer_id_seqÐòÁУ¬¾Í¿ÉÒÔ·ÃÎÊÐòÁеÄcurvalºÍnextvalÊôÐÔ¡£
curval£º·µ»ØÐòÁеĵ±Ç°Öµ
nextval£ºÏÈÔö¼ÓÐòÁеÄÖµ£¬È»ºó·µ»ØÐòÁÐÖµ
ÒÔÏÂsqlÓï¾äÏÈ´´½¨ÁËcustomers±í£¬È»ºó²åÈëÁ½Ìõ¼Ç¼£¬ÔÚ²åÈëʱÉ趨ÁËidºÍname×ֶεÄÖµ£¬ÆäÖÐid×ֶεÄÖµÀ´×ÔÓÚcustomer_id_seqÐòÁС£×îºó²éѯcustomers±íÖеÄid×ֶΡ£
create table customers(id int primary key not null, name varchar(15));
insert into customers values(customer_id_seq.curval, "name1"),(customer_id_seq.nextval, "name2");
select id from customers;
Èç¹ûÔÚoracleÖÐÖ´ÐÐÒÔÉÏÓï¾ä£¬²éѯ½á¹ûΪ£º
id
1
3
http://blog.csdn.net/andyelvis/archive/2008/05/14/2446865.aspx
Ïà¹ØÎĵµ£º
OracleÊý¾Ýµ¼Èëµ¼³öimp/exp¾ÍÏ൱ÓÚoracleÊý¾Ý»¹ÔÓ뱸·Ý¡£expÃüÁî¿ÉÒÔ°ÑÊý¾Ý´ÓÔ¶³ÌÊý¾Ý¿â·þÎñÆ÷µ¼³öµ½±¾µØµÄdmpÎļþ£¬impÃüÁî¿ÉÒÔ°ÑdmpÎļþ´Ó±¾µØµ¼Èëµ½Ô¶´¦µÄÊý¾Ý¿â·þÎñÆ÷ÖС£
ÀûÓÃÕâ¸ö¹¦ÄÜ¿ÉÒÔ¹¹½¨Á½¸öÏàͬµÄÊý¾Ý¿â£¬Ò»¸öÓÃÀ´²âÊÔ£¬Ò»¸öÓÃÀ´ÕýʽʹÓá£
¡¡¡¡Ö´Ðл·¾³£º¿ÉÒÔÔÚSQLPLUS.EXE»òÕßDOS(ÃüÁîÐÐ)ÖÐÖ´ÐУ¬DOSÖ ......
Ò»¡¢²ÎÊýÉèÖÃ
--1¡¢ÉèÖÃA£º
db_block_size = 8192
db_domain = ''
db_file_multiblock_read_count = 16
db_name = bidata
db_recovery_file_dest = /export/home/app/oracle/oracle/product/10.2.0/db_1/flash_recovery_area
db_recovery_file_dest_size = 10737418240
dispatchers = '(PROTOCOL=TCP) (SERVICE=b ......
££Õª×Ô¡¶PB8.0½ø½×ƪ¡·
ÔÚ°²×°ÁËOracle¿Í»§¶Ë³ÌÐòºó£¬ÔÚOracle°²×°Ä¿Â¼ÏÂÓÐÈçÏÂĿ¼ºÍÎļþÊÇÁ¬½ÓOracleÊý¾Ý¿â·þÎñÆ÷Ëù±ØÐèµÄ£º£¨×îºÃ±£³ÖĿ¼²ã´Î¹ØÏµ½á¹¹£©
Oracle\BINĿ¼ÒÔ¼°ÏÂÃæµÄËùÓÐDLLÎļþ£¬²¢ÇÒ±£Ö¤Ó¦ÓóÌÐò¿ÉÒÔÕÒµ½¸ÃĿ¼£¬¼´¸ÃĿ¼ ......
SQL ServerÀïµÄ ISNULL Óë Oracle ÖÐµÄ NULLIF²»Í¬:
SQL Server ÖÐÓÐÁ½¸ö²ÎÊý£¬Óï·¨£º
ISNULL(check_expression, replacement_value)
check_expression Óë replacement_value Êý¾ÝÀàÐͱØÐëÒ»ÖÂ
Èç¹û check_expression Ϊ NULL£¬Ôò·µ»Ø replacement_v ......
PERCONA PERFORMANCE CONFERENCE 2009ÉÏ£¬À´×ÔÑÅ»¢µÄ¼¸Î»¹¤³Ìʦ´øÀ´ÁËһƪ”Efficient Pagination Using MySQL“µÄ±¨¸æ£¬ÓкܶàÁÁµã£¬±¾ÎÄÊÇÔÚÔÎÄ»ù´¡ÉϵĽøÒ»²½ÑÓÉì¡£
Ê×ÏÈ¿´Ò»Ï·ÖÒ³µÄ»ù±¾ÔÀí£º
mysql> explain SELECT * from message ORDER BY id DESC LIMIT 10000, 20\G
***************** 1. row ** ......