postgres/doc/FAQ_chinese_simp
Bruce Momjian 28ebe6b5d0 Update Chinese FAQs to have two versions, a traditional Chinese version (Taiwan)
and a Simplified version (China (PRC)).

Backpatch to 8.2.X.

Daojing.Zhou
2007-02-21 16:42:36 +00:00

802 lines
29 KiB
Plaintext
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

PostgreSQL 常è§é®é¢ï¼FAQï¼
æè¿æ´æ°ï¼2007 å¹´ 1 æ 30 æ¥ ææäº 17:37:01 EST
䏿çæè¿æ´æ°ï¼2007 å¹´ 2 æ 1 æ¥ ææå 12:55:04 CST
ç®åç»´æ¤äººåï¼Bruce Momjian (pgman@candle.pha.pa.us)
䏿çç»´æ¤äººåï¼Daojing.Zhouï¼doudou586@gmail.comï¼
æ¬ææ¡£çææ°çæ¬å¯ä»¥å¨
http://www.postgresql.org/files/documentation/faqs/FAQ.htmlæ¥çã
䏿ä½ç³»ç»å¹³å°ç¸å³çé®é¢å¯å¨http://www.postgresql.org/docs/faq/éæ¾å°ç­
æ¡ã
_________________________________________________________________
常è§é®é¢
1.1)PostgreSQL æ¯ä»ä¹ï¼è¯¥æä¹åé³ï¼
1.2)è°æ§å¶å管çPostgreSQL ï¼
1.3)PostgreSQLççææ¯ä»ä¹ï¼
1.4)PostgreSQLå¯ä»¥è¿è¡å¨åªäºæä½ç³»ç»å¹³å°ä¸ï¼
1.5)æä»åªéè½å¾å°PostgreSQLï¼
1.6)ææ°ççPostgreSQL æ¯ä»ä¹ï¼
1.7)æä»åªéè½å¾å°å¯¹PostgreSQL çæ¯æï¼
1.8)æå¦ä½æäº¤ä¸ä¸ªBUGæ¥åï¼
1.9)æå¦ä½äºè§£å·²ç¥ç BUG ææç¼ºçåè½ï¼
1.10)è½å¤è·åçææ°ææ¡£æåªäºï¼
1.11)æåºè¯¥ææ ·å¦ä¹ SQL ï¼
1.12)å¦ä½æäº¤è¡¥ä¸ææ¯å å¥å¼åéä¼ï¼
1.13)PostgreSQL åå¶ä»æ°æ®åºç³»ç»æ¯èµ·æ¥å¦ä½ï¼
1.14)PostgreSQL å¯ä»¥å¤çæè¿å个å½å®¶å¤æ¶å¶çåååï¼
ç¨æ·å®¢æ·ç«¯é®é¢
2.1)æä»¬å¯ä»¥ç¨ä»ä¹è¯è¨åPostgreSQL æäº¤éï¼
2.2)æä»ä¹å·¥å·å¯ä»¥æPostgreSQL ç¨äº Web 页é¢ï¼
2.3)PostgreSQL æ¥æå¾å½¢ç¨æ·çé¢åï¼
ç³»ç»ç®¡çé®é¢
3.1)æææ ·æè½æPostgreSQL è£å¨ /usr/local/pgsql 以å¤çå°æ¹ï¼
3.2)æå¦ä½æ§å¶æ¥èªå¶ä»çµèçè¿æ¥ï¼
3.3)æææ ·è°æ´æ°æ®åºæå¡å¨ä»¥è·å¾æ´å¥½çæ§è½ï¼
3.4)PostgreSQL éå¯ä»¥è·å¾ä»ä¹æ ·çè°è¯ç¹æ§ï¼
3.5)为ä»ä¹å¨è¯å¾è¿æ¥ç»å½æ¶æ¶å°âSorry, too many clientsâ æ¶æ¯ï¼
3.6)PostgreSQLçå级è¿ç¨æåªäºå容ï¼
3.7)(使ç¨PostgreSQL)æéè¦ä½¿ç¨ä»ä¹è®¡ç®æºç¡¬ä»¶ ï¼
æä½é®é¢
4.1) å¦ä½åªéæ©ä¸ä¸ªæ¥è¯¢ç»æç头å è¡ï¼ææ¯éæºçä¸è¡ï¼
4.2)
å¦ä½æ¥ç表ãç´¢å¼ãæ°æ®åºä»¥åç¨æ·çå®ä¹ï¼å¦ä½æ¥çpsqléç¨å°çæ¥è¯¢æä»¤å¹¶æ¾ç
¤ºå®ä»¬ï¼
4.3) å¦ä½æ´æ¹ä¸ä¸ªåæ®µçæ°æ®ç±»åï¼
4.4) åæ¡è®°å½ï¼å个表ï¼ä¸ä¸ªæ°æ®åºçæå¤§éå¶æ¯å¤å°ï¼
4.5) åå¨ä¸ä¸ªå¸åçææ¬æä»¶éçæ°æ®éè¦å¤å°ç£ç空é´ï¼
4.6) 为ä»ä¹æçæ¥è¯¢å¾æ¢ï¼ä¸ºä»ä¹è¿äºæ¥è¯¢æ²¡æå©ç¨ç´¢å¼ï¼
4.7) æå¦ä½æè½çå°æ¥è¯¢ä¼å卿¯ææ ·è¯ä¼°å¤çæçæ¥è¯¢çï¼
4.8) æææ ·åæ£åè¡¨è¾¾å¼æç´¢å大å°åæ å³çæ­
£åè¡¨è¾¾å¼æ¥æ¾ï¼ææ ·å©ç¨ç´¢å¼è¿è¡å¤§å°åæ 峿¥æ¾ï¼
4.9) å¨ä¸ä¸ªæ¥è¯¢éï¼æææ ·æ£æµä¸ä¸ªå段æ¯å¦ä¸º
NULLï¼æå¦ä½æè½åç¡®æåºèä¸è®ºæå段æ¯å¦å«NULLå¼ï¼
4.10) åç§å符类åä¹é´æä»ä¹ä¸åï¼
4.11.1) æææ ·å建ä¸ä¸ªåºåå·åææ¯èªå¨éå¢çåæ®µï¼
4.11.2) æå¦ä½è·å¾ä¸ä¸ªæå¥çåºåå·çå¼ï¼
4.11.3) åæ¶ä½¿ç¨ currval() ä¼å¯¼è´åå¶ä»ç¨æ·çå²çªæåµåï¼
4.11.4) 为ä»ä¹ä¸å¨äºå¡å¼å¸¸ä¸æ¢åéç¨åºåå·å¢ï¼ä¸ºä»ä¹å¨åºåå·å段çåå¼ä¸­
åå¨é´æå¢ï¼
4.12) ä»ä¹æ¯ OIDï¼ä»ä¹æ¯ CTID ï¼
4.13) 为ä»ä¹ææ¶å°é误信æ¯âERROR: Memory exhausted in
AllocSetAlloc()âï¼
4.14) æå¦ä½æè½ç¥éæè¿è¡ç PostgreSQL ççæ¬ï¼
4.15) æå¦ä½å建ä¸ä¸ªç¼ºç弿¯å½åæ¶é´çåæ®µï¼
4.16) å¦ä½æ§è¡å¤è¿æ¥ï¼outer joinï¼æ¥è¯¢ï¼
4.17) å¦ä½æ§è¡æ¶åå¤ä¸ªæ°æ®åºçæ¥è¯¢ï¼
4.18) å¦ä½è®©å½æ°è¿åå¤è¡æå¤åæ°æ®ï¼
4.19) 为ä»ä¹æå¨ä½¿ç¨PL/PgSQL彿°åå临æ¶è¡¨æ¶ä¼æ¶å°é误信æ¯ârelation
with OID ##### does not existâï¼
4.20) ç®åæåªäºæ°æ®å¤å¶æ¹æ¡å¯ç¨ï¼
4.21) ä¸ºä½æ¥è¯¢ç»ææ¾ç¤ºç表åæååä¸æçæ¥è¯¢è¯å¥ä¸­
çä¸åï¼ä¸ºä½å¤§åç¶æä¸è½ä¿çï¼
_________________________________________________________________
常è§é®é¢
1.1)PostgreSQL æ¯ä»ä¹ï¼è¯¥æä¹åé³ï¼
PostgreSQL è¯»ä½ Post-Gres-Q-Lï¼ææ¶åä¹ç®ç§°ä¸ºPostgres
ãæ³å¬ä¸ä¸å¶åé³ç人åå¯ä»è¿éä¸è½½å£°é³æä»¶ï¼ MP3 æ ¼å¼ ã
PostgreSQL
æ¯é¢åç®æ çå³ç³»æ°æ®åºç³»ç»ï¼å®å·æä¼ ç»å䏿°æ®åºç³»ç»çææåè½ï¼åæ¶å嫿å°å
¨ä¸ä¸ä»£ DBMS ç³»ç»ç使ç¨çå¢å¼ºç¹æ§ãPostgreSQL
æ¯èªç±åè´¹çï¼å¹¶ä¸æææºä»£ç é½å¯ä»¥è·å¾ã
PostgreSQL
çå¼åéä¼ä¸»è¦ä¸ºå¿æ¿èï¼ä»ä»¬éå¸ä¸çåå°å¹¶éè¿äºèç½è¿è¡èç³»ï¼è¿æ¯ä¸ä¸ªç¤¾å
ºå¼å项ç®ï¼å®ä¸è¢«ä»»ä½å¬å¸æ§å¶ã
妿³å å¥å¼åéä¼ï¼è¯·åè§å¼å人å常è§é®é¢ï¼FAQï¼
http://www.postgresql.org/files/documentation/faqs/FAQ_DEV.html
1.2) è°æ§å¶PostgreSQL ï¼
å¦æä½ å¨å¯»æ¾PostgreSQLçæé¨äººï¼ææ¯ä»ä¹ä¸­
央å§åä¼ï¼ææ¯ä»ä¹æå±å¬å¸ï¼ä½ åªè½æ¾å¼äº---å 为ä¸ä¸ªä¹ä¸å­
å¨ï¼ä½æä»¬çç¡®æä¸ä¸ª
æ ¸å¿å§åä¼åCVS管çç»ï¼ä½è¿äºå·¥ä½ç»ç设ç«ä¸»è¦æ¯ä¸ºäºè¿è¡ç®¡çå·¥ä½è䏿
¯å¯¹PostgreSQLè¿è¡ç¬å 弿§å¶ï¼PostgreSQLé¡¹ç®æ¯ç±ä»»ä½äººå
å¯åå çå¼å人å社åºåææç¨æ·æ§å¶çï¼ä½ æéè¦åçå°±æ¯è®¢éé®ä»¶å表ï¼åä¸è®¨è®º
å³å¯ï¼è¦åä¸PostgreSQLçå¼åè¯¦è§ å¼å人å常é®é¢ (Developer's FAQ)
è·åä¿¡æ¯ï¼ã
1.3)PostgreSQLççææ¯ä»ä¹?
PostgreSQLçåå¸éµä»ç»å¸çBSDçæãå®åè®¸ç¨æ·ä¸éç®çå°ä½¿ç¨PostgreSQLï¼çè³ä½
å¯ä»¥éå®PostgreSQLèä¸å«æºä»£ç ä¹å¯ä»¥ï¼å¯ä¸çéå¶å°±æ¯ä½ ä¸è½å 软件èªè
º«é®é¢èåæä»¬è¿½è¯æ³å¾è´£ä»»ï¼å¦å¤å°±æ¯è¦æ±ææç软件æ·è´ä¸­
须忬以ä¸çæå£°æãä¸é¢å°±æ¯æä»¬æä½¿ç¨çBSDçæå£°æå容ï¼
PostgreSQLæ°æ®åºç®¡çç³»ç»
é¨åçæï¼cï¼1996-2005ï¼PostgreSQL å¨çå¼åå°ç»ï¼é¨åçæï¼cï¼1994-1996
å å·å¤§å¦è£äº
ï¼Portions copyright (c) 1996-2005,PostgreSQL Global Development Group
Portions Copyright (c) 1994-6 Regents of the University of
Californiaï¼
å许为任ä½ç®ç使ç¨ï¼æ·è´ï¼ä¿®æ¹åååè¿ä¸ªè½¯ä»¶åå®çææ¡£è䏿¶åä»»ä½è´¹ç
¨ï¼ 并䏿 é¡»ç¾ç½²å æ­
¤è产ççè¯æï¼åææ¯ä¸é¢ççæå£°æåæ¬æ®µä»¥åä¸é¢ä¸¤æ®µæååºç°å¨æææ·è´ä¸ã
ï¼Permission to use, copy, modify, and distribute this software and
its documentation for any purpose, without fee, and without a written
agreement is hereby granted, provided that the above copyright notice
and this paragraph and the following two paragraphs appear in all
copies.ï¼
å¨ä»»ä½æåµä¸ï¼å å·å¤§å¦é½ä¸æ¿æå ä½¿ç¨æ­
¤è½¯ä»¶åå¶ææ¡£è导è´ç对任ä½å½äºäººçç´æ¥çï¼
é´æ¥çï¼ç¹æ®çï¼éå çæèç¸ä¼´èççæåï¼åæ¬å©çæå¤±ç责任ï¼å³ä½¿å å·å¤§å­
¦å·²ç»å»ºè®®äºè¿äºæå¤±çå¯è½æ§æ¶ä¹æ¯å¦æ¤ã
ï¼IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY
PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS
SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA
HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.ï¼
å å·å¤§å¦æç¡®æ¾å¼ä»»ä½ä¿è¯ï¼åæ¬ä½ä¸å±éäºæä¸ç¹å®ç¨éçåä¸åå©ççéå«ä¿è¯ã
è¿éæä¾çè¿ä»½è½¯ä»¶æ¯åºäºâå½ä½æ¯âçåºç¡çï¼å èå å·å¤§å­
¦æ²¡æè´£ä»»æä¾ç»´æ¤ï¼æ¯æï¼æ´æ°ï¼å¢å¼ºæèä¿®æ¹çæå¡ã
ï¼THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,
UPDATES, ENHANCEMENTS, OR MODIFICATIONS.ï¼
1.4)PostgreSQL å¯ä»¥è¿è¡å¨åªäºæä½ç³»ç»å¹³å°ä¸ï¼
ä¸è¬è¯´æ¥ï¼ä»»ä½ç°å¨å¯¹ UNIX å¼å®¹çæä½ç³»ç»ä¹ä¸é½è½è¿è¡PostgreSQL
ãå¨å®è£æåéååºäºå叿¶ç»è¿æç¡®æµè¯çå¹³å°ã
PostgreSQlä¹å¯ä»¥ç´æ¥è¿è¡å¨åºäºå¾®è½¯Windows-NTçæä½ç³»ç»ï¼å¦Win2000
SP4ï¼WinXP å Win2003ï¼å·²å¶ä½å®æçå®è£åå¯ä»
http://pgfoundry.org/projects/pginstallerä¸è½½ï¼åºäºMSDOSçWindowsæä½ç³
»ç» ï¼Win95ï¼Win98ï¼WinMeï¼éè¦éè¿Cygwin模æç¯å¢è¿è¡PostgreSQLã
忶乿ä¸ä¸ªä¸ºNovell Netware 6å¼åççæ¬å¯ä»
http://forge.novell.comè·åï¼ä¸ºOS/2(eComStation)å¼åççæ¬å¯ä»
http://hobbes.nmsu.edu/cgi-bin/h-search?sh=1&button=Search&key=postgre
SQL&stype=all&sort=type&dir=%2F ä¸è½½ã
1.5) æä»åªéè½å¾å°PostgreSQLï¼
éè¿æµè§å¨å¯ä»http://www.postgresql.org/ftp/ä¸è½½ï¼ä¹å¯éè¿FTPï¼ä»
ftp://ftp.PostgreSQL.org/pub/ç«ç¹ä¸è½½ã
1.6) ææ°ççPostgreSQLæ¯ä»ä¹ï¼
PostgreSQL ææ°ççæ¬æ¯çæ¬ 8.2.1 ã
æä»¬è®¡åæ¯å¹´åå¸ä¸ä¸ªä¸»è¦åçº§çæ¬ï¼æ¯å 个æåå¸ä¸ä¸ªå°çæ¬ã
1.7) æä»åªéè½å¾å°å¯¹PostgreSQLçæ¯æï¼
PostgreSQL社åºéè¿é®ä»¶å表为å¶å¤§å¤æ°ç¨æ·æä¾å¸®å©ï¼è®¢éé®ä»¶å表ç主
ç«ç¹æ¯
http://www.postgresql.org/community/lists/ï¼ä¸è¬æåµä¸ï¼åå å¥General æ
Bugé®ä»¶å表æ¯ä¸ä¸ªè¾å¥½çå¼å§ã
主è¦çIRCé¢éæ¯å¨FreeNode(irc.freenode.net)ç#postgresqlï¼ä¸ºäºè¿ä¸æ­
¤é¢éï¼å¯ä»¥ä½¿ç¨UNIXç¨åºircï¼å¶æä»¤æ ¼å¼ï¼ irc -c '#postgresql'
"$USER" irc.freenode.net ï¼æè使ç¨å¶ä»IRC客æ·ç«¯ç¨åºã卿¤ç½ç»ä¸è¿å­
å¨ä¸ä¸ªPostgreSQLç西ççé¢é(#postgersql-es)åæ³è¯é¢é
(#postgresql-fr)ãåæ ·å°ï¼å¨EFNETä¸ä¹æä¸ä¸ªPostgreSQLç交æµé¢éã
坿ä¾å䏿¯æçå¬å¸å表å¯å¨http://techdocs.postgresql.org/companies.phpæµ
è§ã
1.8) æå¦ä½æäº¤ä¸ä¸ªBUGæ¥åï¼
å¯è®¿é®
http://www.postgresql.org/support/submitbugï¼å¡«åBug䏿¥è¡¨æ ¼å³å¯ï¼åæ
·ä¹å¯è®¿é®ftpç«ç¹ftp://ftp.PostgreSQL.org/pub/
æ£æ¥ææ æ´æ°çPostgreSQLçæ¬æè¡¥ä¸ã
éè¿ä½¿ç¨Bugæäº¤è¡¨æ ¼ææ¯åå¾PostgreSQLé®ä»¶å表çBugé叏伿以ä¸ä¹ä¸åå¤ï
¼
* ææäº¤å容䏿¯ä¸ä¸ªBugåå¶ä¸æ¯Bugçåå ã
* ææäº¤å容æ¯ä¸ä¸ªå·²ç¥çBugå¹¶ä¸å·²ç»å å¥TODOå¾å¤çä»»å¡å表ã
* ææäº¤çBugå·²å¨å½åçæ¬ä¸è¢«ä¿®æ£ã
* ææäº¤çBug已修æ£ä½å°æªå°è¡¥ä¸å å¥ç°å¨çåå¸è½¯ä»¶åã
* è¯·æ±æäº¤èæä¾æ´è¯¦ç»çä¿¡æ¯ï¼
+ æä½ç³»ç»
+ PostgreSQLçæ¬
+ å¯éç°Bugçæµè¯æ¡ä¾
+ è°è¯ä¿¡æ¯
+ è°è¯è·è¸ªè¾åº
* ææäº¤å容æ¯ä¸ä¸ªæ°Bugï¼å°æ§è¡ä»¥ä¸å·¥ä½ï¼
+ å建ä¸ä¸ªæ°è¡¥ä¸å¹¶å°å¶å å¥ä¸ä¸ä¸ªä¸»è¦çæ¬ææ¯å°çæ¹è¿çæ¬ä¸ã
+ æ¤Bugææ¶ä¸è½ä¿®æ£ï¼å°è¢«å è³TODOå¾å¤çä»»å¡å表ã
1.9) æå¦ä½äºè§£å·²ç¥ç BUG ææç¼ºçåè½ï¼
PostgreSQL æ¯æä¸ä¸ªæ©å±ç SQL:2003 çåéãåéæä»¬çTODO
å表ï¼äºè§£å·²ç¥Bugå表ãæç¼ºçåè½åå°æ¥çå¼å计åã
è¦æ±å¢å æ°åè½çç³è¯·é叏伿¶å°ä»¥ä¸ä¹ä¸çåå¤ï¼
* 该åè½å·²å å¥TODOå¾å¤çä»»å¡å表ã
* 该åè½ä¸æ¯å¿é¡»çï¼å 为ï¼
+ 宿¯ç°æçä¸ç¬¦åSQLæ åçæåè½çéå¤ã
+ 该åè½æ§ä¼å¤§å¤§å¢å 代ç ç夿ç¨åºï¼è带æ¥ç好夿¯å¾®ä¸è¶³éçã
+ 该åè½æ¯ä¸å®å¨ææ¯ä¸å¯é çã
* 该åè½å°è¢«å å¥TODOå¾å¤çä»»å¡å表ã
PostgreSQLä¸ä½¿ç¨Bugè·è¸ªç³»ç»ï¼å 为æä»¬åç°å¨é®ä»¶å表中
ç´æ¥åå¤ä»¥åä¿è¯TODOä»»å¡åè¡¨æ»æ¯å¤äºææ°ç¶æçæ¹å¼å·¥ä½æç伿´é«ä¸äºãäºå®ä
¸ï¼Bugä¸ä¼å¨æä»¬ç软件ä¸åå¨å¾é¿æ¶é´ï¼
对影åå¾å¤ç¨æ·çBug乿»æ¯å¾å¿«ä¼è¢«ä¿®æ£ãå¯ä¸è½æ¾å°æææ¹è¿ãæé«åä¿®æ­
£çå°æ¹æ¯CVSçæ¥å¿ä¿¡æ¯ï¼å³ä½¿æ¯å¨è½¯ä»¶æ°çæ¬çåå¸ä¿¡æ¯ä¸­
ä¹ä¸ä¼ååºæ¯ä¸å¤çè½¯ä»¶æ´æ°ã
1.10) è½å¤è·åçææ°ææ¡£æåªäºï¼
PostgreSQLåå«å¤§éçææ¡£ï¼ä¸»è¦æè¯¦ç»çåèæåï¼æå页åä¸äºçæµè¯ä¾åãåè§ /doc
ç®å½ï¼è¯æ³¨ï¼åºä¸º $PGHOME/docï¼ã
ä½ è¿å¯ä»¥å¨çº¿æµè§PostgreSQLçæåï¼å¶ç½åæ¯ï¼http://www.PostgreSQL.org/d
ocsã
æä¸¤æ¬å³äºPostgreSQLç书å¨çº¿æä¾ï¼å¨
http://www.PostgreSQL.org/docs/awbook.html å
http://www.commandprompt.com/ppbook/ ã 乿大éçPostgreSQL书ç±å¯ä¾è´­
ä¹°ï¼å¶ä¸æä¸ºæµè¡ç䏿¬æ¯ç±Korry Douglasç¼åçãå¨
http://techdocs.PostgreSQL.org/techdocs/bookreviews.phpä¸
䏿大éæå³PostgreSQL书ç±çç®ä»ã å¨
http://techdocs.PostgreSQL.org/䏿¶éäºæå³PostgreSQLç大鿿¯æç« ã
客æ·ç«¯çå½ä»¤è¡ç¨åºpsqlæä¸äºä»¥ \d
å¼å¤´çå½ä»¤ï¼å¯æ¾ç¤ºå³äºç±»åï¼æä½ç¬¦ï¼å½æ°ï¼èåçä¿¡æ¯ï¼ä½¿ç¨ \?
å¯ä»¥æ¾ç¤ºææå¯ç¨çå½ä»¤ã
æä»¬ç web ç«ç¹å嫿´å¤çææ¡£ã
1.11) æåºè¯¥ææ ·å¦ä¹ SQL ï¼
é¦åèèä¸è¿°æå°çä¸PostgreSQLç¸å³ç书ç±ï¼å¦å¤ä¸æ¬æ¯Teach Yourself SQL in
21 Days, Second Editionï¼å¶è¯¦ç»ä»ç»çç½åæ¯
http://members.tripod.com/er4ebus/sql/index.htmï¼
æä»¬ç许å¤ç¨æ·å欢The Practical SQL Handbookï¼ Bowman, Judith S.
ç¼åï¼Addison-Wesleyå¬å¸åºçï¼å¶ä»çå忬¢ The Complete Reference SQL,
Groff ç¼åï¼McGraw-Hillå¬å¸åºçã
å¨ä¸åç½åä¸ä¹æå¾å¥½çæç¨ï¼ä»ä»¬æ¯
* http://www.intermedia.net/support/sql/sqltut.shtm
* http://sqlcourse.com.
* http://www.w3schools.com/sql/default.asp
* http://mysite.verizon.net/Graeme_Birchall/id1.html
1.12)å¦ä½æäº¤è¡¥ä¸ææ¯å å¥å¼åéä¼ï¼
è¯¦è§ å¼å人å常è§é®é¢ (Developer's FAQ) ã
1.13)PostgreSQLåå¶ä»æ°æ®åºç³»ç»æ¯èµ·æ¥å¦ä½ï¼
è¯ä»·è½¯ä»¶æå¥½å ç§æ¹æ³ï¼åè½ï¼æ§è½ï¼å¯é æ§ï¼æ¯æåä»·æ ¼ã
åè½
PostgreSQL æ¥æå¤§ååç¨æ°æ®åºæå¤çåè½ï¼ä¾å¦ï¼äºå¡ï¼å­
æ¥è¯¢ï¼è§¦åå¨ï¼è§å¾ï¼å¤é®åè宿´æ§å夿çéå®çã
æä»¬è¿æä¸äºå®ä»¬æ²¡æçç¹æ§ï¼å¦ç¨æ·å®ä¹ç±»åï¼ç»§æ¿ï¼è§ååå¤çæ¬å¹¶è
¡æ§å¶ä»¥åå°éçäºç¨çã
æ§è½
PostgreSQLåå¶ä»åç¨å弿ºçæ°æ®åºå·æç±»ä¼¼çæ§è½ã对æäºå¤ç宿¯è¾å¿«
ï¼å¯¹å¶ä»ä¸äºå¤ç宿¯è¾æ¢ã ä¸å¶ä»æ°æ®åºç¸æ¯ï¼æä»¬çæ§è½ä¼å£é常å¨
+/- 10%ä¹é´ã
å¯é æ§
æä»¬é½ç¥éæ°æ®åºå¿é¡»æ¯å¯é çï¼å¦åå®å°±ä¸ç¹ç¨é½æ²¡æãæä»¬åªååå°åå¸
ç»è¿è®¤çæµè¯çï¼ç¼ºé·æå°ç稳å®ä»£ç ãæ¯ä¸ªçæ¬è³å°æä¸ä¸ªæç beta
æµè¯æ¶é´ï¼å¹¶ä¸æä»¬çåå¸å岿¾ç¤ºæä»¬å¯ä»¥æä¾ç¨³å®çï¼ç¢åºçï¼å¯ç¨ä
ºç产使ç¨ççæ¬ãæä»¬ç¸ä¿¡å¨è¿æ¹é¢æä»¬ä¸å¶ä»çæ°æ®åºè½¯ä»¶æ¯ç¸å½çã
æ¯æ
æä»¬çé®ä»¶å表æä¾ä¸ä¸ªé常大çå¼å人ååç¨æ·çç»ä»¥å¸®å©è§£å³æç¢°å
°çä»»ä½é®é¢ãæä»¬ä¸è½ä¿è¯æ»æ¯è½è§£å³é®é¢ï¼ç¸æ¯ä¹ä¸ï¼åç¨æ°æ®åºè½¯
ä»¶ä¹å¹¶ä¸æ¯æ»è½å¤æä¾è§£å³æ¹æ³ã
ç´æ¥ä¸å¼å人åï¼ç¨æ·ç¾¤ï¼æååæºç¨åºæ¥è§¦ä½¿PostgreSQLçæ¯ææ¯å¶ä»æ°
æ®åºè¿è¦å¥½ãè¿æä¸äºå䏿§çå¨é¢ææ¯æ¯æï¼å¯ä»¥ç»æä¾ç»é£äºéè¦ç人ãï¼
åé1.7 å°èï¼
ä»·æ ¼
æä»¬å¯¹ä»»ä½ç¨éé½åè´¹ï¼åæ¬åç¨åéåç¨ç®çã
ä½ å¯ä»¥ä¸å éå¶å°åä½ ç产åéå 奿们ç代ç ï¼é¤äºé£äºæä»¬å¨ä¸é¢çç
æå£°æé声æç BSDçæä¹å¤çå容ã
1.14) PostgreSQLå¯ä»¥å¤çæè¿å个å½å®¶å¤æ¶å¶çååå?
PostgreSQL 8.0ä¹åççæ¬æ¯ä½¿ç¨æä½ç³»ç»ä¸­
çæ¶åºæ°æ®åºæ¥å¤ç夿¶å¶çä¿¡æ¯ï¼èª8.0çå以åççæ¬PostgreSQLä¼èªèº«å«æææ°çæ
¶åºä¿¡æ¯ã
_________________________________________________________________
ç¨æ·å®¢æ·ç«¯é®é¢
2.1) æä»¬å¯ä»¥ç¨ä»ä¹è¯è¨åPostgreSQLæäº¤éï¼
PostgreSQL(缺çæåµ)åªå®è£æCåååµå¼Cçæ¥å£ï¼å¶ä»çæ¥å£é½æ¯ç¬ç«ç项ç®ï¼è½å¤
åå«ä¸è½½ï¼è¿äºæ¥å£é¡¹ç®ç¬ç«ç好å¤
æ¯ä»ä»¬å¯ä»¥æåèªçåå¸è®¡åååèªç¬ç«çå¼åç»ã
ä¸äºç¼ç¨è¯­
è¨å¦PHPé½æè®¿é®PostgreSQLçæ¥å£ï¼PerlãTCLãPython以åå¾å¤å¶ä»è¯è¨çæ¥å£å¨
http://gborg.postgresql.orgç½ç«ä¸çDrivers/Interfaceså°è坿¾å°ï¼
å¹¶ä¸éè¿Internetå¾å®¹ææç´¢å°ã
2.2) æä»ä¹å·¥å·å¯ä»¥æPostgreSQLç¨äº Web 页é¢ï¼
ä¸ä¸ªä»ç»ä»¥æ°æ®åºä¸ºåå°çæºä¸éçç«ç¹æ¯ï¼http://www.webreview.comã
å¯¹äº Web éæï¼PHP æ¯ä¸ä¸ªæå¥½çæ¥å£ãå®å¨http://www.php.net/ã
对äºå¤æçä»»å¡ï¼å¾å¤äººéç¨ Perl æ¥å£å 使ç¨CGI.pmçDBD::Pg æ mod_perl ã
2.3)PostgreSQLæ¥æå¾å½¢ç¨æ·çé¢åï¼
åä¸ç¨æ·ææ¯å¼æºå¼å人åè½æ¾å°å¾å¤çæå³PostgreSQLçGUIå¾å½¢å·¥å·è½¯ä»¶ï¼å¨
PostgreSQLç¤¾åºææ¡£æä¸ä¸ªè¯¦ç»çå表ã
_________________________________________________________________
ç³»ç»ç®¡çé®é¢
3.1)æææ ·è½æPostgreSQLè£å¨ /usr/local/pgsql 以å¤çå°æ¹ï¼
å¨è¿è¡ configure æ¶å ä¸ --prefix é项ã
3.2) æå¦ä½æ§å¶æ¥èªå¶ä»çµèçè¿æ¥ï¼
缺çæåµä¸ï¼PostgreSQLåªå许æ¥èªæ¬æºä¸éè¿ unix å奿¥åæTCP/IPæ¹å¼çè¿æ¥ã
ä½ åªæå¨ä¿®æ¹äºéç½®æä»¶postgresql.conf中
çlisten_addressesï¼ä¸ä¹å¨éç½®æä»¶$PGDATA/pg_hba.conf䏿å¼äº
åºäºè¿ç¨çµèï¼ host-based
ï¼ç身份认è¯ï¼å¹¶éæ°å¯å¨PostgreSQLï¼å¦åå¶ä»çµèæ¯ä¸è½ä¸ä½ çPostgreSQL
æå¡å¨è¿è¡è¿æ¥çã
3.3) æææ ·è°æ´æ°æ®åºå¼æä»¥è·å¾æ´å¥½çæ§è½ï¼
æä¸ä¸ªä¸»è¦æ¹é¢å¯ä»¥æåPostgreSQLçæ½è½ã
æ¥è¯¢æ¹å¼çåå
è¿ä¸»è¦æ¶åä¿®æ¹æ¥è¯¢æ¹å¼ä»¥è·åæ´å¥½çæ§è½:
+ å建索å¼ï¼åæ¬è¡¨è¾¾å¼åé¨åç´¢å¼ï¼
+ 使ç¨COPYè¯å¥ä»£æ¿å¤ä¸ªInsertè¯å¥ï¼
+ å°å¤ä¸ªSQLè¯å¥ç»æä¸ä¸ªäºå¡ä»¥åå°æäº¤äºå¡çå¼éï¼
+ ä»ä¸ä¸ªç´¢å¼ä¸æå夿¡è®°å½æ¶ä½¿ç¨CLUSTERï¼
+ ä»ä¸ä¸ªæ¥è¯¢ç»æä¸ååºé¨åè®°å½æ¶ä½¿ç¨LIMITï¼
+ 使ç¨é¢ç¼è¯å¼æ¥è¯¢ï¼Prepared Query)ï¼
+ 使ç¨ANALYZEä»¥ä¿æç²¾ç¡®çä¼åç»è®¡ï¼
+ å®æä½¿ç¨ VACUUM æ pg_autovacuum
+ è¿è¡å¤§éæ°æ®æ´æ¹æ¶åå é¤ç´¢å¼ï¼ç¶åé建索å¼ï¼
æå¡å¨çéç½®
éç½®æä»¶postgres.conf中
çå¾å¤è®¾ç½®é½ä¼å½±åæ§è½ï¼ææåæ°çå表å¯è§ï¼
管çåæå/æ°æ®åºæå¡å¨è¿è¡ç¯å¢/æ°æ®åºæå¡å¨è¿è¡éç½®ï¼
æå³åæ°çè§£éå¯è§ï¼http://www.varlena.com/varlena/GeneralBits/Tid
bits/annotated_conf_e.html å
http://www.varlena.com/varlena/GeneralBits/Tidbits/perf.htmlã
硬件çéæ©
è®¡ç®æºç¡¬ä»¶å¯¹æ§è½çå½±å坿µè§
http://candle.pha.pa.us/main/writings/pgsql/hw_performance/inde
x.html å http://www.powerpostgresql.com/PerfList/ã
3.4)PostgreSQLéå¯ä»¥è·å¾ä»ä¹æ ·çè°è¯ç¹æ§ï¼
PostgreSQL æå¾å¤ç±»ä¼¼ log_*
çæå¡å¨éç½®åéå¯ç¨äºæ¥è¯¢çæå°åè¿ç¨ç»è®¡ï¼èè¿äºå·¥ä½å¯¹è°è¯åæ§è½æµè¯å¾æå¸
®å©ã
3.5) 为ä»ä¹å¨è¯å¾è¿æ¥æ¶æ¶å°âSorry, too many
clientsï¼å·²æå¤ªå¤ç¨æ·è¿æ¥ï¼âæ¶æ¯ï¼
è¿è¡¨ç¤ºä½ 已达å°ç¼ºç100个并ååå°è¿ç¨æ°çéå¶ï¼ä½ éè¦éè¿ä¿®æ¹postgres
ql.confæä»¶ä¸çmax_connections弿¥
å¢å postmasterçåå°å¹¶åå¤çæ°ï¼ä¿®æ¹åééæ°å¯å¨postmasterã
3.6)PostgreSQLçå级è¿ç¨æåªäºå容 ï¼
PostgreSQL å¼åç»å¯¹æ¯æ¬¡å°çæ¬çå级主è¦åªåäºä¸äºBugä¿®æ£å·¥ä½ï¼å æ¤ä»
7.4.8 åçº§å° 7.4.9 ä¸éè¦ dump å restoreï¼ä»éè¦åæ­
¢æ°æ®åºæå¡å¨ï¼å®è£æ´æ°åç软件åï¼ç¶åé坿å¡å¨å³å¯ã
ææPostgreSQLçç¨æ·åºè¯¥å¨ææ¥è¿ï¼ä½ æä½¿ç¨çä¸»çæ¬ï¼çå°æ¹è¿çæ¬åå¸å°½å¿«åç
º§ãå°½ç®¡æ¯æ¬¡å级å¯è½é½æä¸ç¹é£é©ï¼PostgreSQLçå°æ¹è¿çä»ä»æ¯è®¾è®¡ç¨æ¥ä
¿®æ­
£ä¸äºBugçï¼ä»£ç æ¹å¨è¾å°ï¼æä»¥é£é©è¿æ¯å¾å°çãPostgreSQL社åºè®¤ä¸ºä¸è¬æ
åµä¸ä¸å级çé£é©è¿æ¯å¤äºå级çã
ä¸»çæ¬çå级ï¼ä¾å¦ä» 7.3 å° 7.4ï¼é常ä¼ä¿®æ¹ç³»ç»è¡¨åæ°æ®è¡¨çå鍿 ¼å¼ã
è¿äºæ¹åä¸è¬æ¯è¾å¤æï¼å æ¤æä»¬ä¸ç»´ææ°æ®æä»¶çååå¼å®¹æ§ãå æ¤ä»èçæ¬ä¸­
è¿è¡æ°æ®å¯¼åºï¼dumpï¼/ç¶å卿°çæ¬ä¸­
è¿è¡æ°æ®å¯¼å¥ï¼reloadï¼å¯¹ä¸»çæ¬çå级æ¯å¿é¡»çã
3.7)(使ç¨PostgreSQL)æéè¦ä½¿ç¨ä»ä¹è®¡ç®æºç¡¬ä»¶ ï¼
ç±äºè®¡ç®æºç¡¬ä»¶å¤§å¤æ°æ¯å¼å®¹çï¼äººä»¬æ»æ¯å¾åäºç¸ä¿¡ææè®¡ç®æºç¡¬ä»¶è
´¨é乿¯ç¸åçãäºå®ä¸ä¸æ¯ï¼ ECC RAMï¼å¸¦å¥å¶æ ¡éªçååï¼ï¼SCSI
ï¼ç¡¬çï¼åä¼è´¨çä¸»æ¿æ¯ä¸äºä¾¿å®è´§è¦æ´å å¯é ä¸å·ææ´å¥½çæ§è½ãPostgreSQL
å ä¹å¯ä»¥è¿è¡å¨ä»»ä½ç¡¬ä»¶ä¸ï¼
ä½å¦æå¯é æ§åæ§è½å¯¹ä½ çç³»ç»å¾éè¦ï¼ä½ å°±éè¦å¨é¢çç ç©¶ä¸ä¸ä½ ç硬件éç
½®äºã卿们çé®ä»¶å表ä¸ä¹æå³äº 硬件éç½®åæ§ä»·æ¯ç讨论ã
_________________________________________________________________
æä½é®é¢
4.1) å¦ä½åªéæ©ä¸ä¸ªæ¥è¯¢ç»æç头å è¡ï¼ææ¯éæºçä¸è¡ï¼
å¦æä½ åªæ¯è¦æåå è¡æ°æ®ï¼å¹¶ä¸ä½ 卿§è¡æ¥è¯¢ä¸­
ç¥éç¡®åçè¡æ°ï¼ä½ å¯ä»¥ä½¿ç¨LIMITåè½ã 妿æä¸ä¸ªç´¢å¼ä¸ ORDER BY中
çæ¡ä»¶å¹éï¼PostgreSQL å¯è½å°±åªå¤çè¦æ±çå¤´å æ¡è®°å½ï¼
ï¼å¦åå°å¯¹æ´ä¸ªæ¥è¯¢è¿è¡å¤çç´å°çæéè¦çè¡ï¼ã妿卿§è¡æ¥è¯¢åè½æ¶ä¸ç¥éç¡®å
çè®°å½æ°ï¼ å¯ä½¿ç¨æ¸¸æ (cursor)åFETCHåè½ã
å¯ä½¿ç¨ä»¥ä¸æ¹æ³æåä¸è¡éæºè®°å½çï¼
SELECT cols
FROM tab
ORDER BY random()
LIMIT 1 ;
4.2)
å¦ä½æ¥ç表ãç´¢å¼ãæ°æ®åºä»¥åç¨æ·çå®ä¹ï¼å¦ä½æ¥çpsqléç¨å°çæ¥è¯¢æä»¤å¹¶æ¾ç¤ºå®ä»¬
ï¼
å¨psqlä¸ä½¿ç¨ \dt å½ä»¤æ¥æ¾ç¤ºæ°æ®è¡¨çå®ä¹ï¼è¦äºè§£psql中
ç宿´å½ä»¤å表å¯ä½¿ç¨\? ï¼å¦å¤ï¼ä½ ä¹å¯ä»¥é读 psql çæºä»£ç
æä»¶pgsql/src/bin/psql/describe.cï¼å®åæ¬ä¸ºçæpsqlåææ å½ä»¤çè¾åºçææ SQL
å½ä»¤ãä½ è¿å¯ä»¥å¸¦ -E é项å¯å¨ psqlï¼ è¿æ ·å®å°æå°åºä½ å¨psql中
æç»åºçå½ä»¤æ§è¡æ¶çåé¨å®é使ç¨çSQLæ¥è¯¢è¯­
å¥ãPostgreSQL乿ä¾äºä¸ä¸ªå¼å®¹SQLçINFORMATION SCHEMAæ¥å£ï¼
ä½ å¯ä»¥ä»è¿éè·åå³äºæ°æ®åºçä¿¡æ¯ã
å¨ç³»ç»ä¸ä¹æä¸äºä»¥pg_ æå¤´çç³»ç»è¡¨ä¹æè¿°äºè¡¨çå®ä¹ã
ä½¿ç¨ psql -l æä»¤å¯ä»¥ååºææçæ°æ®åºã
ä¹å¯ä»¥æµè§ä¸ä¸
pgsql/src/tutorial/syscat.sourceæä»¶ï¼å®å举äºå¾å¤å¯ä»æ°æ®åºç³»ç»è¡¨ä¸
è·åä¿¡æ¯çSELECTè¯æ³ã
4.3) å¦ä½æ´æ¹ä¸ä¸ªåæ®µçæ°æ®ç±»åï¼
å¨8.0çæ¬éæ´æ¹ä¸ä¸ªåæ®µçæ°æ®ç±»åå¾å®¹æï¼å¯ä½¿ç¨ ALTER TABLE ALTER
COLUMN TYPE ã
å¨ä»¥åççæ¬ä¸ï¼å¯ä»¥è¿æ ·åï¼
BEGIN;
ALTER TABLE tab ADD COLUMN new_col new_data_type;
UPDATE tab SET new_col = CAST(old_col AS new_data_type);
ALTER TABLE tab DROP COLUMN old_col;
COMMIT;
ä½ ç¶åå¯ä»¥ä½¿ç¨VACUUM FULL tab æä»¤æ¥ä½¿ç³»ç»æ¶åæ ææ°æ®æå ç¨ç空é´ã
4.4) åæ¡è®°å½ï¼å个表ï¼åä¸ªæ°æ®åºçæå¤§éå¶æ¯å¤å°ï¼
ä¸é¢æ¯ä¸äºéå¶ï¼
åä¸ªæ°æ®åºæå¤§å°ºå¯¸ï¼ æ éå¶ï¼å·²å卿 32TB çæ°æ®åºï¼
å个表çæå¤§å°ºå¯¸ï¼ 32 TB
ä¸è¡è®°å½çæå¤§å°ºå¯¸ï¼ 1.6 TB
ä¸ä¸ªå段çæå¤§å°ºå¯¸? 1 GB
ä¸ä¸ªè¡¨éæå¤§è¡æ°ï¼ æ éå¶
ä¸ä¸ªè¡¨éæå¤§åæ°ï¼ 250-1600 ï¼ä¸åç±»åæå³ï¼
ä¸ä¸ªè¡¨éçæå¤§ç´¢å¼æ°éï¼ æ éå¶
å½ç¶ï¼å®é䏿²¡æçæ£çæ éå¶ï¼è¿æ¯è¦åå¯ç¨ç£ç空é´ãå¯ç¨åå/交æ¢åºçå¶çº¦ã
äºå®ä¸ï¼å½ä¸è¿°è¿äºæ°å¼åå¾å¼å¸¸å°å¤§æ¶ï¼ç³»ç»æ§è½ä¹ä¼åå¾å¤§å½±åã
å表çæå¤§å¤§å° 32 TB
ä¸éè¦æä½ç³»ç»å¯¹å个æä»¶ä¹éè¿ä¹å¤§çæ¯æã大表ç¨å¤ä¸ª 1 GB çæä»¶å­
å¨ï¼å æ¤æä»¶ç³»ç»å¤§å°çéå¶æ¯ä¸éè¦çã
å¦æç¼ºççå大å°å¢é¿å° 32K ï¼æå¤§çå表大å°åæå¤§åæ°è¿å¯ä»¥å¢å å°ååã
æä¸ä¸ªéå¶å°±æ¯ä¸è½å¯¹å¤§å°å¤äº2000å­
èçåå建索å¼ã幸è¿å°æ¯è¿æ ·çç´¢å¼å¾å°ç¨å°ãéè¿å¯¹å¤å­
èåçå容è¿è¡MD5åç¨è¿ç®ç»æè¿è¡å½æ°ç´¢å¼å¯å¯¹åçå¯ä¸æ§å¾å°ä¿è¯ï¼
å¹¶ä¸å¨ææ£ç´¢å许对åä¸çåè¯è¿è¡æç´¢ã
4.5) åå¨ä¸ä¸ªå¸åçææ¬æä»¶éçæ°æ®éè¦å¤å°ç£ç空é´ï¼
ä¸ä¸ª Postgres æ°æ®åºï¼å­
å¨ä¸ä¸ªææ¬æä»¶ï¼æå ç¨çç©ºé´æå¤å¯è½éè¦ç¸å½äºè¿ä¸ªææ¬æä»¶èªèº«å¤§å°5åçç£
ç空é´ã
ä¾å¦ï¼å设æä¸ä¸ª 100,000 è¡çæä»¶ï¼æ¯è¡æä¸ä¸ªæ´æ°åä¸ä¸ªææ¬æè¿°ã
åè®¾ææ¬ä¸²çå¹³åé¿åº¦ä¸º20åèãææ¬æä»¶å ç¨ 2.8 MBãå­
æ¾è¿äºæ°æ®çPostgreSQLæ°æ®åºæä»¶å¤§çº¦æ¯ 6.4 MB:
28 åè: æ¯è¡ç头ï¼å¤§çº¦å¼ï¼
24 åè: ä¸ä¸ªæ´æ°ååæ®µåä¸ä¸ªææ¬ååæ®µ
+ 4 åè: 页é¢åæååç»çæé
----------------------------------------
56 åèæ¯è¡
PostgreSQL æ°æ®é¡µç大尿¯ 8192 åè (8 KB)ï¼åï¼
8192 åèæ¯é¡µ
------------------- = 146 è¡/æ°æ®é¡µï¼åä¸åæ´ï¼
56 åèæ¯è¡
100000 æ°æ®è¡
-------------------- = 685 æ°æ®é¡µï¼åä¸åæ´ï¼
146 è¡/æ°æ®é¡µ
685 æ°æ®é¡µ * 8192 åè/页 = 5,611,520 åèï¼5.6 MBï¼
ç´¢å¼ä¸éè¦è¿ä¹å¤çé¢å¤æ¶èï¼ä½ä¹ç¡®å®åæ¬è¢«ç´¢å¼çæ°æ®ï¼å æ­
¤å®ä»¬ä¹å¯è½å¾å¤§ã
空å¼NULLåæ¾å¨ä½å¾ä¸ï¼å æ¤å ç¨å¾å°ç空é´ã
4.6) 为ä»ä¹æçæ¥è¯¢å¾æ¢ï¼ä¸ºä»ä¹è¿äºæ¥è¯¢æ²¡æå©ç¨ç´¢å¼ï¼
å¹¶éæ¯ä¸ªæ¥è¯¢é½ä¼èªå¨ä½¿ç¨ç´¢å¼ãåªæå¨è¡¨ç大å°è¶è¿ä¸ä¸ªæå°å¼ï¼å¹¶ä¸æ¥
询åªä¼éä¸è¡¨ä¸è¾å°æ¯ä¾çè®°å½æ¶æä¼éç¨ç´¢å¼ã
è¿æ¯å ä¸ºç´¢å¼æ«æå¼èµ·çéå³ç£çååå¯è½æ¯ç´æ¥å°è¯»å表ï¼é¡ºåºæ«æï¼æ´æ¢ã
为äºå¤æ­
æ¯å¦ä½¿ç¨ç´¢å¼ï¼PostgreSQLå¿é¡»è·å¾æå³è¡¨çç»è®¡å¼ãè¿äºç»è®¡å¼å¯ä»¥ä½¿ç
¨ VACUUM ANALYZEï¼æ ANALYZE è·å¾ã 使ç¨ç»è®¡å¼ï¼ä¼åå¨ç¥é表中
æå¤å°è¡ï¼å°±è½å¤æ´å¥½å°å¤ææ¯å¦å©ç¨ç´¢å¼ã
ç»è®¡å¼å¯¹ç¡®å®ä¼åçè¿æ¥é¡ºåºåè¿æ¥æ¹æ³ä¹å¾æç¨ãå¨è¡¨çå容åçååæ¶ï¼åºå®æè¿
è¡ç»è®¡å¼çæ´æ°æ¶éã
ç´¢å¼é常ä¸ç¨äº ORDER BY
ææ§è¡è¿æ¥ã对ä¸ä¸ªå¤§è¡¨ç䏿¬¡é¡ºåºæ«æåå䏿¬¡æåºé常æ¯ç´¢å¼æ«æè¦å¿«ãç¶
èï¼å¦æå° LIMIT å ORDER BY
ç»åå¨ä¸èµ·ä½¿ç¨çè¯ï¼é常å°ä¼ä½¿ç¨ç´¢å¼ï¼å ä¸ºè¿æ¶ä»è¿å表中
çä¸å°é¨åè®°å½ã
å¦æä½ ç¡®ä¿¡PostgreSQLçä¼åå¨ä½¿ç¨é¡ºåºæ«ææ¯ä¸æ£ç¡®çï¼ä½ å¯ä»¥ä½¿ç¨SET
enable_seqscan TO 'off'æä»¤æ¥å³éé¡ºåºæ«æï¼
ç¶å忬¡è¿è¡æ¥è¯¢ï¼ä½ å°±å¯ä»¥çåºä½¿ç¨ä¸ä¸ªç´¢å¼æ«ææ¯å¦ç¡®å®è¦å¿«ä¸äºã
å½ä½¿ç¨éé符æä½ï¼ä¾å¦ LIKE æ ~ æ¶ï¼ç´¢å¼åªè½å¨ç¹å®çæåµä¸ä½¿ç¨ï¼
* å符串çå¼å§é¨åå¿é¡»æ¯æ®éå符串ï¼ä¹å°±æ¯è¯´ï¼
+ LIKE 模å¼ä¸è½ä»¥ % æå¤´ã
+ ~ ï¼æ£å表达å¼ï¼æ¨¡å¼å¿é¡»ä»¥ ^ æå¤´ã
* å符串ä¸è½ä»¥å¹éå¤ä¸ªåç¬¦çæ¨¡å¼ç±»æå¤´ï¼ä¾å¦ [a-e]ã
* 大å°åæ å³çæ¥æ¾ï¼å¦ ILIKE å ~* çä¸ä½¿ç¨ç´¢å¼ï¼ä½å¯ä»¥ç¨ 4.8
èæè¿°ç表达å¼ç´¢å¼ã
* å¨å initdb æ¶å¿é¡»éç¨ç¼ºççæ¬å°è®¾ç½® C
localeï¼å 为系ç»ä¸å¯è½ç¥éå¨éC localeæåµæ¶ä¸ä¸ä¸ªæå¤§å符æ¯ä»ä¹ã
å¨è¿ç§æåµä¸ï¼ä½ å¯ä»¥å建ä¸ä¸ªç¹æ®çtext_pattern_opsç´¢å¼æ¥ç¨äºLIKE
çç´¢å¼ã
å¨8.0ä¹åççæ¬ä¸­
ï¼é¤éè¦æ¥è¯¢çæ°æ®ç±»ååç´¢å¼çæ°æ®ç±»åç¸å¹éï¼å¦åç´¢å¼ç»å¸¸æ¯æªè¢«ç¨å°ï¼ç
¹å«æ¯å¯¹int2,int8åæ°å¼åçç´¢å¼ã
4.7) æå¦ä½æè½çå°æ¥è¯¢ä¼å卿¯ææ ·è¯ä¼°å¤çæçæ¥è¯¢ï¼
åè EXPLAIN æå页ã
4.8) æææ ·åæ£åè¡¨è¾¾å¼æç´¢å大å°åæ å³çæ­
£åè¡¨è¾¾å¼æ¥æ¾ï¼ææ ·å©ç¨ç´¢å¼è¿è¡å¤§å°åæ 峿¥æ¾ï¼
æä½ç¬¦ ~ å¤çæ£å表达å¼å¹éï¼è ~* å¤ç大å°åæ å³çæ­
£å表达å¼å¹éã大å°åæ å³ç LIKE åç§æä¸º ILIKEã
大å°åæ å³çç弿¯è¾é常ååï¼
SELECT *
FROM tab
WHERE lower(col) = 'abc';
è¿æ ·å°ä¸ä¼ä½¿ç¨æ åçç´¢å¼ã使¯å¯ä»¥å建ä¸ä¸ªå¨è¿ç§æåµä¸ä½¿ç¨ç表达å¼ç
´¢å¼:
CREATE INDEX tabindex ON tab (lower(col));
妿ä¸è¿°ç´¢å¼å¨å建æ¶å å¥UNIQUE约æï¼è½ç¶ç´¢å¼å段èªèº«å容å¯ä»¥å­
å¨å¤§å°åä¸éçå容ï¼ä½å¦ææUNIQUE约æåï¼è¿äºå容ä¸è½ä»ä»æ¯å¤§å°åä¸åï¼å¦åä
¼é æå²çªï¼ã为äºä¿è¯ä¸åçè¿ç§æåµï¼å¯ä»¥ä½¿ç¨CHECKçº¦ææ¡ä»¶ææ¯è§¦åå¨å¨å½
奿¶è¿è¡éå¶ã
4.9) å¨ä¸ä¸ªæ¥è¯¢éï¼æææ ·æ£æµä¸ä¸ªå段æ¯å¦ä¸º NULL ï¼æå¦ä½æè½åç¡®æåºèä¸è®ºæå­
段æ¯å¦å« NULL å¼ï¼
ç¨ IS NULL å IS NOT NULL æµè¯è¿ä¸ªå段ï¼å·ä½æ¹æ³å¦ä¸ï¼
SELECT *
FROM tab
WHERE col IS NULL;
为äºè½å¯¹å« NULLåæ®µæåºï¼å¯å¨ ORDER BY æ¡ä»¶ä¸ä½¿ç¨ IS NULLå IS NOT
NULL ä¿®é¥°ç¬¦ï¼æ¡ä»¶ä¸ºç true å°æ¯æ¡ä»¶ä¸ºåfalse æå¨åé¢ï¼ä¸é¢çä¾å­
å°±ä¼å°å« NULL çè®°å½æå¨ç»æçä¸é¢é¨åï¼
SELECT *
FROM tab
ORDER BY (col IS NOT NULL)
4.10) åç§å符类åä¹é´æä»ä¹ä¸åï¼
ç±»å åé¨åç§° 说æ
VARCHAR(n) varchar æå®äºæå¤§é¿åº¦ï¼åé¿å­
符串ï¼ä¸è¶³å®ä¹é¿åº¦çé¨åä¸è¡¥é½
CHAR(n) bpchar å®é¿å符串ï¼å®éæ°æ®ä¸è¶³å®ä¹é¿åº¦æ¶ï¼ä»¥ç©ºæ ¼è¡¥é½
TEXT text 没æç¹å«çä¸ééå¶ï¼ä»åè¡çæå¤§é¿åº¦éå¶ï¼
BYTEA bytea åé¿åèåºåï¼ä½¿ç¨NULLåç¬¦ä¹æ¯å许çï¼
"char" char å个å符
å¨ç³»ç»è¡¨åå¨ä¸äºé误信æ¯éä½ å°çå°åé¨åç§°ã
ä¸é¢æåçååç§ç±»åæ¯"varlena"ï¼åé¿ï¼ç±»åï¼ä¹å°±æ¯è¯´ï¼å¼å¤´çå个å­
èæ¯é¿åº¦ï¼åé¢ææ¯æ°æ®ï¼ã äºæ¯å®éå ç¨çç©ºé´æ¯å£°æç大å°è¦å¤ä¸äºã
ç¶èè¿äºç±»åå¦å®ä¹å¾é¿æ¶é½å¯ä»¥è¢«å缩åå¨ï¼å æ­
¤ç£ç空é´ä¹å¯è½æ¯é¢æ³çè¦å°ã
VARCHAR(n) å¨åå¨éå¶äºæå¤§é¿åº¦çåé¿åç¬¦ä¸²æ¯æå¥½çã TEXT éç¨äºå­
卿大å¯è¾¾ 1Gå·¦å³ä½æªå®ä¹éå¶é¿åº¦çå符串ã
CHAR(n) æéåäºåå¨é¿åº¦ç¸åçå符串ã CHAR(n)伿 ¹æ®æç»å®çå­
段é¿åº¦ä»¥ç©ºæ ¼è¡¥è¶³ï¼ä¸è¶³çåæ®µå容ï¼ï¼ è VARCHAR(n) åªå­
卿ç»å®çæ°æ®å容ã BYTEA ç¨äºåå¨äºè¿å¶æ°æ®ï¼å°¤å¶æ¯åå« NULL å­
èçå¼ãè¿äºç±»åå·æå·®ä¸å¤çæ§è½ã
4.11.1) æææ ·å建ä¸ä¸ªåºåå·ææ¯èªå¨éå¢çåæ®µï¼
PostgreSQL æ¯æ SERIAL æ°æ®ç±»åãï¼å­
段å®ä¹ä¸ºSERIALåï¼å°èªå¨å建ä¸ä¸ªåºåçæå¨ï¼ä¾å¦ï¼
CREATE TABLE person (
id SERIAL,
name TEXT
);
ä¼èªå¨è½¬æ¢ä¸ºä»¥ä¸SQLè¯å¥ï¼
CREATE SEQUENCE person_id_seq;
CREATE TABLE person (
id INT4 NOT NULL DEFAULT nextval('person_id_seq'),
name TEXT
);
åè create_sequence æå页è·åå³äºåºåçæå¨çæ´å¤ä¿¡æ¯ã
4.11.2) æå¦ä½è·å¾ä¸ä¸ªæå¥çåºåå·çå¼ï¼
ä¸ç§æ¹æ³æ¯å¨æå¥ä¹ååç¨å½æ° nextval() ä»åºåå¯¹è±¡éæ£ç´¢åºä¸ä¸ä¸ª SERIAL
å¼ï¼ç¶ååç¨æ¤å¼ç²¾ç¡®å°æå¥ãä½¿ç¨ 4.11.1 éçä¾è¡¨ï¼å¯ç¨ä¼ªç è¿æ ·æè¿°ï¼
new_id = execute("SELECT nextval('person_id_seq')");
execute("INSERT INTO person (id, name) VALUES (new_id, 'Blaise Pascal')");
è¿æ ·è¿è½å¨å¶ä»æ¥è¯¢ä¸ä½¿ç¨åæ¾å¨ new_id éçæ°å¼ï¼ä¾å¦ï¼ä½ä¸ºåç§ person
表çå¤é®ï¼ã 注æèªå¨å建ç SEQUENCE 对象çåç§°å°ä¼æ¯
<table>_<serialcolumn>_seqï¼ è¿é table å serialcolumn
å嫿¯ä½ ç表çåç§°åä½ ç SERIAL åæ®µçåç§°ã
类似çï¼å¨ SERIAL 对象缺çæå¥åä½ å¯ä»¥ç¨å½æ° currval() æ£ç´¢åèµå¼ç
SERIAL å¼ï¼ä¾å¦ï¼
execute("INSERT INTO person (name) VALUES ('Blaise Pascal')");
new_id = execute("SELECT currval('person_id_seq')");
4.11.3) åæ¶ä½¿ç¨ currval() ä¼å¯¼è´åå¶ä»ç¨æ·çå²çªæåµåï¼
ä¸ä¼ãcurrval() è¿åçæ¯ä½ æ¬æ¬¡ä¼è¯è¿ç¨æèµçå¼è䏿¯ææç¨æ·çå½åå¼ã
4.11.4) 为ä»ä¹ä¸å¨äºå¡å¼å¸¸ä¸æ¢åéç¨åºåå·å¢ï¼ä¸ºä»ä¹å¨åºåå·å段çåå¼ä¸åå¨é´æ­
å¢ï¼
ä¸ºäºæé«å¹¶åæ§ï¼åºåå·å¨éè¦çæ¶åèµäºæ­
£å¨è¿è¡çäºå¡ï¼å¹¶ä¸å¨äºå¡ç»æä¹åä¸è¿è¡éå®ï¼ è¿å°±ä¼å¯¼è´å¼å¸¸ä¸­
æ¢çäºå¡åï¼åºåå·ä¼åºç°é´éã
4.12) ä»ä¹æ¯ OID ï¼ä»ä¹æ¯ CTID ï¼
PostgreSQL
éåå»ºçæ¯ä¸è¡è®°å½é½ä¼è·å¾ä¸ä¸ªå¯ä¸çOIDï¼é¤éå¨å建表æ¶ä½¿ç¨WITHOUT
OIDSé项ã OIDå建æ¶ä¼èªå¨çæä¸ä¸ª4åèçæ´æ°ï¼ææ OID
å¨ç¸åºPostgreSQLæå¡å¨ä¸åæ¯å¯ä¸çã ç¶èï¼å®å¨è¶è¿40亿æ¶å°æº¢åºï¼ OIDæ­
¤åä¼åºç°éå¤ãPostgreSQL å¨å®çåé¨ç³»ç»è¡¨éä½¿ç¨ OID å¨è¡¨ä¹é´å»ºç«èç³»ã
å¨ç¨æ·çæ°æ®è¡¨ä¸ï¼æå¥½æ¯ä½¿ç¨SERIAlæ¥ä»£æ¿OID
å 为SERIALåªè¦ä¿è¯å¨å个表中
çæ°å¼æ¯å¯ä¸çå°±å¯ä»¥äºï¼è¿æ ·å®æº¢åºçå¯è½æ§å°±é常å°äºï¼
SERIAL8å¯ç¨æ¥ä¿å8åèçåºåæ°å¼ã
CTID ç¨äºæ è¯å¸¦çæ°æ®åï¼å°åï¼åï¼ååï¼åç§»çç¹å®çç©çè¡ã CTID
å¨è®°å½è¢«æ´æ¹æéè½½ååçæ¹åãç´¢å¼æ°æ®ä½¿ç¨å®ä»¬æåç©çè¡ã
4.13) 为ä»ä¹ææ¶å°é误信æ¯âERROR: Memory exhausted in AllocSetAlloc()âï¼
è¿å¾å¯è½æ¯ç³»ç»çèæååç¨åäºï¼æèåæ ¸å¯¹æäºèµæºæè¾ä½çéå¶å¼ãå¨å¯å¨
postmaster ä¹åè¯è¯ä¸é¢çå½ä»¤ï¼
ulimit -d 262144
limit datasize 256m
åå³äºä½ ç¨ç
shellï¼ä¸é¢å½ä»¤åªæä¸æ¡è½æåï¼ä½æ¯å®å°æä½ çè¿ç¨æ°æ®æ®µéå¶è®¾å¾æ¯è¾é«ï¼
å èä¹è®¸è½è®©æ¥è¯¢å®æãè¿æ¡å½ä»¤åºç¨äºå½åè¿ç¨ï¼ä»¥åææå¨è¿æ¡å½ä»¤è¿è¡ååå
»ºçåè¿ç¨ã
å¦æä½ æ¯å¨è¿è¡SQL客æ·ç«¯æ¶å 为åå°è¿åäºå¤ªå¤çæ°æ®èåºç°é®é¢ï¼è¯·å¨è¿è¡
客æ·ç«¯ä¹åæ§è¡ä¸è¿°å½ä»¤ã
4.14) æå¦ä½æè½ç¥éæè¿è¡çPostgreSQLççæ¬ï¼
ä» psql éï¼è¾å¥ SELECT version();æä»¤ã
4.15) æå¦ä½å建ä¸ä¸ªç¼ºç弿¯å½åæ¶é´çåæ®µï¼
ä½¿ç¨ CURRENT_TIMESTAMPï¼
CREATE TABLE test (x int, modtime TIMESTAMP DEFAULT CURRENT_TIMESTAMP );
4.16) æææ ·è¿è¡ outer join ï¼å¤è¿æ¥ï¼ï¼
PostgreSQL éç¨æ åç SQL è¯æ³æ¯æå¤è¿æ¥ãè¿éæ¯ä¸¤ä¸ªä¾åï¼
SELECT *
FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col);
ææ¯
SELECT *
FROM t1 LEFT OUTER JOIN t2 USING (col);
è¿ä¸¤ä¸ªçä»·çæ¥è¯¢å¨ t1.col å t2.col ä¸åè¿æ¥ï¼å¹¶ä¸è¿å t1 中
æææªè¿æ¥çè¡ï¼é£äºå¨ t2 䏿²¡æå¹éçè¡ï¼ã å³[å¤]è¿æ¥ï¼RIGHT OUTER
JOINï¼å°è¿å t2 䏿ªè¿æ¥çè¡ã å®å¨å¤è¿æ¥ï¼FULL OUTER JOINï¼å°è¿å t1 å t2
䏿ªè¿æ¥çè¡ã å³é®å OUTER å¨å·¦[å¤]è¿æ¥ãå³[å¤]è¿æ¥åå®å¨[å¤]è¿æ¥ä¸­
æ¯å¯éçï¼æ®éè¿æ¥è¢«ç§°ä¸ºåè¿æ¥ï¼INNER JOINï¼ã
4.17) å¦ä½ä½¿ç¨æ¶åå¤ä¸ªæ°æ®åºçæ¥è¯¢ï¼
没æåæ³æ¥è¯¢å½åæ°æ®åºä¹å¤çæ°æ®åºã
å 为PostgreSQLè¦å è½½ä¸æ°æ®åºç¸å³çç³»ç»ç®å½ï¼ç³»ç»è¡¨ï¼ï¼å æ­
¤è·¨æ°æ®åºçæ¥è¯¢å¦ä½æ§è¡æ¯ä¸å®çã
éå å¢å¼æ¨¡åcontrib/dblinkå许éç¨å½æ°è°ç¨å®ç°è·¨åºæ¥è¯¢ãå½ç¶ç¨æ·ä¹å¯ä»¥
åæ¶è¿æ¥å°ä¸åçæ°æ®åºæ§è¡æ¥è¯¢ç¶åå¨å®¢æ·ç«¯åå¹¶ç»æã
4.18) å¦ä½è®©å½æ°è¿åå¤è¡æå¤åæ°æ®ï¼
å¨å½æ°ä¸è¿åæ°æ®è®°å½éçåè½æ¯å¾å®¹æä½¿ç¨çï¼è¯¦æåè§ï¼
http://techdocs.postgresql.org/guides/SetReturningFunctions
4.19) 为ä»ä¹æå¨ä½¿ç¨PL/PgSQL彿°åå临æ¶è¡¨æ¶ä¼æ¶å°é误信æ¯ârelation with
OID ##### does not existâï¼
PL/PgSQLä¼ç¼å彿°çèæ¬å容ï¼ç±æ¤å¸¦æ¥çä¸ä¸ªä¸å¥½çå¯ä½ç¨æ¯è¥ä¸ä¸ª
PL/PgSQL
彿°è®¿é®äºä¸ä¸ªä¸´æ¶è¡¨ï¼ç¶å该表被å é¤å¹¶é建äºï¼å忬¡è°ç¨è¯¥å½æ°å
°å¤±è´¥ï¼ å 为ç¼åç彿°å容ä»ç¶æåæ§ç临æ¶è¡¨ãè§£å³çæ¹æ³æ¯å¨ PL/PgSQL
ä¸ç¨EXECUTE
对临æ¶è¡¨è¿è¡è®¿é®ãè¿æ ·ä¼ä¿è¯æ¥è¯¢å¨æ§è¡åæ»ä¼è¢«éæ°è§£æã
4.20) ç®åæåªäºæ°æ®å¤å¶æ¹æ¡å¯ç¨ï¼
âå¤å¶âåªæ¯ä¸ä¸ªæ¯è¯ï¼æå¥½å ç§å¤å¶ææ¯å¯ç¨ï¼æ¯ç§é½æä¼ç¹å缺ç¹ï¼
主/ä»å¤å¶æ¹å¼æ¯å许ä¸ä¸ªä¸»æå¡å¨æ¥å读/åçç³è¯·ï¼èå¤ä¸ªä»æå¡å¨åªè½æ¥åè
¯»/SELECTæ¥è¯¢çç³è¯·ï¼ ç®åææµè¡ä¸åè´¹ç主/ä»PostgreSQLå¤å¶æ¹æ¡æ¯
Slony-I ã
å¤ä¸ªä¸»æå¡å¨çå¤å¶æ¹å¼å许å°è¯»/åçç³è¯·åéç»å¤å°çè®¡ç®æºï¼è¿ç§æ¹å¼ç±äºé
è¦å¨å¤å°æå¡å¨ä¹é´åæ¥æ°æ®åå¨
å¯è½ä¼å¸¦æ¥è¾ä¸¥éçæ§è½æå¤±ï¼Pgclusteræ¯ç®åè¿ç§æ¹æ¡ 中
æå¥½çï¼èä¸è¿å¯ä»¥åè´¹ä¸è½½ã
乿ä¸äºåä¸éä»è´¹ååºäºç¡¬ä»¶çæ°æ®å¤å¶æ¹æ¡ï¼æ¯æä¸è¿°åç§å¤å¶æ¨¡åã
4.21) ä¸ºä½æ¥è¯¢ç»ææ¾ç¤ºç表åæååä¸æçæ¥è¯¢è¯å¥ä¸çä¸åï¼ä¸ºä½å¤§åç¶æä¸è½ä¿çï¼
æå¸¸è§çåå æ¯å¨å建表æ¶å¯¹è¡¨åææ¯åå使ç¨äºåå¼å·ââï¼å½ä½¿ç¨äºåå¼å·åï¼è¡
¨åæååï¼ç§°ä¸ºæ è¯ç¬¦ï¼å卿¶æ¯åºå 大å°åçï¼
è¿æè°çä½ å¨æ¥è¯¢æ¶è¡¨åæååä¹åºä½¿ç¨åå¼å·ï¼ä¸äºå·¥å·è½¯ä»¶ï¼åpgAdminä¼å¨
ååºå建表çæä»¤æ¶èªå¨å°å¨æ¯ä¸ªæ è¯ç¬¦ä¸å åå¼å·ã å æ­
¤ï¼ä¸ºäºæ è¯ç¬¦çç»ä¸ï¼ä½ åºè¯¥ï¼
* å¨å建表æ¶é¿åå°æ è¯ç¬¦ä½¿ç¨åå¼å·å¼èµ·æ¥ã
* 卿 è¯ç¬¦ä¸åªä½¿ç¨å°å忝ã
* ï¼ä¸ºäºä¸å·²åå¨çæ è¯ç¬¦ç¸åï¼å¨æ¥è¯¢ä¸ä½¿ç¨åå¼å·å°æ è¯ç¬¦å¼èµ·æ¥ã