SQL傪暘愅偡傞崅搙側僥僋僯僢僋丗DB2僠儏乕僯儞僌丒儀僗僩僾儔僋僥傿僗乮6乯乮4/4 儁乕僕乯

丂SQL僗僥乕僩儊儞僩偺幚峴僷僼僅乕儅儞僗傪偝傜偵岦忋偝偣傞偨傔偺僥僋僯僢僋傪偄偔偮偐徯夘偟傑偡丅

丂屻懕偺埵抲巜掕UPDATE僗僥乕僩儊儞僩偵傛偭偰峏怴偝傟傞壜擻惈偺偁傞峴傪曐岇偡傞偵偼丄乽SELECT 乧 FOR UPDATE乿傪巊梡偟傑偡丅偙傟偵傛傝丄慖戰偝傟傞偡傋偰偺峴偵峏怴儘僢僋乮U乯偑偐偗傜傟傑偡丅偙傟偼丄屻偱峴傪峏怴偡傞応崌偵僨僢僪儘僢僋偑敪惗偡傞偺傪杊偖偨傔偵栶棫偪傑偡丅

丂寢壥昞偑撉傒庢傝愱梡偱偁傞偙偲傪柧帵偡傞偵偼丄乽SELECT 乧 FOR READ ONLY乮傑偨偼FETCH ONLY乯乿傪巊梡偟傑偡丅偙偺応崌丄埵抲巜掕UPDATE僗僥乕僩儊儞僩傗埵抲巜掕DELETE僗僥乕僩儊儞僩偺拞偱僇乕僜儖傪嶲徠偡傞偙偲偼偱偒傑偣傫丅偙偺傛偆偵偡傞偲丄DB2偑僽儘僢僉儞僌乮1偮偺FETCH梫媮偱僋儔僀傾儞僩偵懳偟偰暋悢偺峴傪栠偡偙偲乯傪幚峴偱偒傞傛偆偵側傞偨傔丄FETCH憖嶌偺僷僼僅乕儅儞僗偑岦忋偟傑偡丅

丂乽SELECT 乧 OPTIMIZE FOR n ROWS乿傪巊梡偟偰丄墳摎帪娫傪嵟揔壔偟傑偡丅偙傟偵傛傝僆僾僥傿儅僀僓偼丄墳摎僙僢僩慡懱偺僐僗僩傪嵟彫尷偵梷偊傞乮僨僼僅儖僩偺摦嶌乯戙傢傝偵丄n峴傪慺憗偔栠偡傛偆偵偟傑偡丅傑偨丄READ ONLY暥愡傪巊梡偟偰偄傞応崌偼丄偦傟偧傟偺僽儘僢僋撪偱栠偝傟傞峴悢偵塭嬁傪梌偊傑偡乮1偮偺僽儘僢僋撪偱偼嵟戝偱n峴偑栠偝傟傑偡乯丅偙傟偼丄僼僃僢僠壜擻側峴悢傪惂尷偡傞傕偺偱偼偁傝傑偣傫偑丄n峴傛傝懡偔偺峴傪僼僃僢僠偡傞偲僷僼僅乕儅儞僗偑掅壓偟傑偡丅僨乕僞丒僶僢僼傽偑偙偺暥愡偺塭嬁傪庴偗傞傛偆偵偡傞偨傔偵偼丄乽n亊峴僒僀僘乿偺抣偑乮DBM CFG RQRIOBLK傑偨偼ASLHEAPSZ偵傛偭偰掕媊偝傟傞乯捠怣僶僢僼傽偺僒僀僘傪挻偊偰偼偄偗傑偣傫丅

丂乽SELECT 乧 FETCH FIRST n ROWS乿傪巊梡偡傞偲丄徠夛寢壥僙僢僩偺僒僀僘傪惂尷偱偒傑偡丅

丂乽ALTER TABLE 乧 ACTIVATE NOT LOGGED INITIALLY WITH EMPTY TABLE乿傪巊梡偡傞偲丄戝検偺DELETE乮僷乕僕乯傪幚尰偱偒傑偡丅偙偺憖嶌偼儘僌偵婰榐偝傟側偄偨傔丄壗偐栤戣偑敪惗偟偨応崌偼丄昞傪僪儘僢僾偟側偗傟偽側傝傑偣傫丅傛傝埨慡側曽朄偼丄REPLACE僆僾僔儑儞偲嬻偺僼傽僀儖傪巜掕偟偰丄IMPORT儐乕僥傿儕僥傿傪巊梡偡傞偙偲偱偡丅

丂儘僢僋懸婡傗僨僢僪儘僢僋偺壜擻惈傪尭傜偡偵偼丄commit傪巊梡偟偰昿斏偵儘僢僋傪夝曻偟傑偡丅

丂僗僥乕僩儊儞僩傪孞傝曉偟幚峴偡傞応崌偼丄儕僥儔儖偱偼側偔僷儔儊乕僞丒儅乕僇乕傪巊梡偟傑偡丅OLTP偱偼僐儞僷僀儖帪娫偑廳梫偵側傞偨傔丄儕僥儔儖傪僷儔儊乕僞丒儅乕僇乕偵抲偒姺偊傞偙偲偵傛傝丄僐儞僷僀儖偺孞傝曉偟傪夞旔偟傑偡丅僷儔儊乕僞丒儅乕僇乕傪巊梡偡傞応崌丄僆僾僥傿儅僀僓偼抣偑嬒堦偵暘嶶偟偰偄傞偲壖掕偡傞偨傔丄僨乕僞偵曃傝偑偁傞偲揔愗側傾僋僙僗丒僾儔儞偑慖戰偝傟傑偣傫丅堦斒揑偵丄OLAP娐嫬偺曽偑偙偺塭嬁傪傛傝嫮偔庴偗傑偡丅

丂嵶暘惈傪崅傔丄僷僼僅乕儅儞僗偲暲峴惈傪岦忋偝偣傞偵偼丄暘棧儗儀儖傪僗僥乕僩儊儞僩丒儗儀儖偱巜掕偟傑偡丅DB2偱偼丄UR乮Uncommitted Read丗旕僐儈僢僩撉傒庢傝乯丄CS乮Cursor Stability丗僇乕僜儖屌掕乯丄RS乮Read Stability丗撉傒庢傝屌掕乯丄RR乮Repeatable Read丗斀暅壜擻撉傒庢傝乯偑僒億乕僩偝傟偰偄傑偡丅椺偊偽乽SELECT * FROM STAFF WITH UR乿偲偡傞偲丄旕僐儈僢僩撉傒庢傝乮嵟彫尷偺儘僢僋乯傪巊梡偟偰SELECT偑幚峴偝傟傑偡丅

丂僨乕僞偑嬒堦偵暘嶶偟偰偄側偄応崌偼丄慖戰惈乮selectivity乯傪巜掕偡傞偲曋棙偱偡丅慖戰惈偲偼丄峴偑弎晹傪枮偨偡乮偡側傢偪恀偵側傞乯壜擻惈偺偙偲偱偡丅傛傝尷掕揑側弎晹偑朷傑偟偄偲偄偊傑偡丅偦偺傛偆側弎晹偼丄乮偦偺屻偺張棟傪峴偆乯墘嶼巕偵懳偟偰傛傝彮側偄峴傪栠偡偨傔丄徠夛傪姰椆偡傞偺偵昁梫側CPU偺晧壸偲擖弌椡偺悢偑彮側偔偰嵪傒傑偡丅

丂椺偊偽丄100枩峴偺昞偵懳偡傞弎晹偺慖戰惈偑0.01乮1亾乯偱偁傞応崌丄1枩峴偑弎晹傪枮偨偟丄99枩峴偑弎晹傪枮偨偝側偄偲尒愊傕傜傟傞偙偲傪堄枴偟傑偡丅

丂僨乕僞偑嬒堦偵暘嶶偟偰偄傞偲偄偆壖掕傪偦偺傑傑巊偆偺偱偼側偔丄屘堄偵掅偄抣乮椺偊偽0.000001乯傪慖戰惈偵巜掕偡傞偙偲偵傛傝丄僆僾僥傿儅僀僓偑偦偺楍偺嶕堷傪巊梡偡傞傛偆偵乽曐徹乿偱偒傑偡丅偙偺曽朄偼丄昞偑戝偒偔側傞偲梊憐偝傟傞偑丄摿掕偺楍偺嶕堷偑忢偵巊梡偝傟傞傛偆偵曐徹偟偨偄応崌偵曋棙偱偡丅慖戰惈偵乽1乿傪巜掕偡傞偲丄DB2偑摿掕偺楍偺嶕堷傪巊梡偟側偄傛偆偵巜帵偡傞偙偲偑偱偒傑偡丅

丂偙偺僥僋僯僢僋偱偼丄嵟揔壔儗儀儖偵乽5乿乮椺偊偽丄DFT_QUERYOPT=5乯傪巜掕偡傞偲丄嵟傕梊憐偳偍傝偵摦嶌偟傑偡丅傑偨丄SELECTIVITY暥愡傪巊梡偡傞偵偼丄傑偢弶傔偵儗僕僗僩儕曄悢乽DB2_SELECTIVITY=YES乿傪愝掕偟偰僀儞僗僞儞僗傪嵞巒摦偡傞昁梫偑偁傝傑偡丅

丂SELECTIVITY暥愡偼丄埲壓偺弎晹偵懳偟偰巜掕偱偒傑偡丅