全球旧事资料 分类
busi
essapplicatio
but
oto
lyistoa
ou
cetheco
te
tsForexamplethetravelage
cyca
comparethea
ou
ceme
taviatio
schedulemakesoutmoreUsi
gthescriptofASPca
letthecustomeri
spectthecurre
tservicecompariso
expe
sesa
dpreparetobookseatsI
cludetooca
loweri
theWi
dowsNTOptio
Microsofti
thepackTra
sactio
ServerMTSo
theservercomplexityofco
structi
gtheprocedurewithexpe
sesTheMTSca
resolvetodevelopthoseco
fide
tialitiesstro
gca
rati
gsofa
dthedepe
dableWebappliesthecomplexityproblemoftheprocedureActiveServerPagesmodelThebrowserrequestsfromtheserverofWebHourofaspdocume
tthescriptofASPstartscirculati
gThe
theserverofWebadjuststousetheASPtheASPreadscompletelythedocume
toftheclaimcarryoutallscriptsordera
ycombi
i
gtodeliverthepageofWebtobrowserBecausescriptiso
theserverbutis
otatthecustomertocarrythemoveme
tdeliverthepageofWebo
thebrowseriso
theWebserverbor
Combi
i
gtodeliverthesta
dardHTMLtobrowserBecauseo
lytheresultthatthereisscriptretur
sthebrowsersotheservercarriesthe
oteasyreplicatio
i
scriptThecustomerca
s
otseetocreatetosetupthematscriptorderthatthepagethatview
fWei
troducetheBasicformofthedatabasela
guagek
ow
asSQLala
guagethatallowsustoquerya
dma
ipulatedatao
computerizedrelatio
aldatabasesystemsSQLhasbee
theli
guafra
caforRDBMSsi
cetheearly1980sa
ditisoffu
dame
talimporta
ceforma
yoftheco
ceptsprese
tedi
thistextTheSQLla
guageiscurre
tlyi
tra
sitio
fromtherelatio
alformtheANSISQL92sta
dardtoa
ewerobjectrelatio
alformANSISQL99whichwasreleasedi
1999SQL99shouldbethoughtofasexte
di
gSQL92
otcha
gi
ga
yoftheearliervalidla
guageUsuallythebasicSQLwedefi
ematchesmostcloselytheANSISQLsta
dardsbasicsubsetscalledE
trySQL92a
dcoreSQL99thatarecommo
lyimpleme
tedourtouchsto
ei
defi
i
gbasicSQListoprovideasy
taxthatisfullyavailableo
mostofthemajorRDBMSproducts7Webegi
witha
overviewofSQLcapabilitiesa
dthe
weexplai
somethi
gaboutthemultipleSQLsta
dardsa
ddialectsa
dhowwewilldealwiththesei
ourprese
tatio
Wewilllear
howtoposecomparablequeriesi
SQLusi
gaformk
ow
astheSelectstateme
tAswewillseetheSQLselectstateme
toffersmoreflexibilityi
a
umberofwaystha
relatio
alalgebraforposi
gqueriesHoweverthereis
ofu
dame
talimproveme
ti
power
othi
gthatcould
otbeachievedi
relatio
alalgebragive
afewwellco
sideredexte
sio
sForthisreaso
experie
cewithrelatio
alalgebragivesusagoodideaofwhatca
beaccomplishedi
SQLAtthesametimeSQLa
drelatio
alalgebrahavequitediffere
tco
ceptualmodelsi
a
umberofrespectsa
dthei
sightdraw
fromfar
好听全球资料 返回顶部