Video: Vim li cas cov txheej txheem khaws cia sai dua?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Koj nqe lus ntawd Cov txheej txheem khaws cia yog sai dua tshaj SQL Queries tsuas yog qee qhov tseeb. Yog li koj hu rau khaws cov txheej txheem dua, lub cav SQL thawj zaug tshawb nrhiav los ntawm nws cov npe ntawm cov lus nug cov phiaj xwm thiab yog tias nws pom qhov sib tw, nws siv cov phiaj xwm optimized.
Ib yam li ntawd, tib neeg nug, vim li cas cov txheej txheem khaws cia sai dua li kev ua haujlwm?
Cov txheej txheem khaws cia tuaj yeem yog ceev , heev ceev , raws li lawv pre-compiled. Tus optimiser tsis tas yuav ua kom tiav cov phiaj xwm ua tiav txhua lub sijhawm. A Cov txheej txheem khaws cia yuav rov qab tau cov txiaj ntsig hauv ib daim ntawv. Muaj nuj nqi tuaj yeem yog Scalar (rov qab ib qho txiaj ntsig) lossis xa cov ntaub ntawv Tabular.
Tsis tas li ntawd, cov txheej txheem khaws cia sai npaum li cas ntawm cov lus nug? " Cov txheej txheem khaws cia yog precompiled thiab cached ces qhov kev ua tau zoo heev zoo dua ." Cov txheej txheem khaws cia yog precompiled thiab optimised, uas txhais tau hais tias cov nug cav tuaj yeem tua lawv sai dua. Los ntawm qhov sib txawv, lus nug hauv code yuav tsum tau parsed, compiled, thiab optimized ntawm runtime. Qhov no tag nrho cov nqi sijhawm.
Kuj tseem paub yog, cov txheej txheem khaws cia puas nce kev ua haujlwm?
Reusability ntawm Cached Query Plans Cov txheej txheem khaws cia zoo dua database kev ua tau zoo raws li lawv tso cai cov lus nug hauv cached yuav rov siv dua. Nyob rau hauv qhov tsis muaj cov phiaj xwm kev nug lus nug, SQL neeg rau zaub mov cia li pom qhov tsis muaj thiab tsim cov lus nug cached uas ua rau txhim kho kev ua tau zoo.
Vim li cas thiaj siv cov txheej txheem khaws cia?
A khaws cov txheej txheem muab cov txheej txheem tseem ceeb ntawm kev ruaj ntseg ntawm tus neeg siv interface thiab cov ntaub ntawv. Nws txhawb kev ruaj ntseg los ntawm kev tswj cov ntaub ntawv vim tias cov neeg siv kawg tuaj yeem nkag lossis hloov cov ntaub ntawv, tab sis tsis txhob sau cov txheej txheem . Nws txhim kho cov khoom tsim tau vim cov lus hais hauv a khaws cov txheej txheem tsuas yog yuav tsum tau sau ib zaug.
Pom zoo:
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Cov txheej txheem khaws cia muab kev ua tau zoo dua qub vim tias kev hu tsawg dua yuav tsum raug xa mus rau cov ntaub ntawv. Piv txwv li, yog tias cov txheej txheem khaws cia muaj plaub nqe lus SQL hauv cov lej, ces tsuas yog xav tau ib qho kev hu mus rau cov ntaub ntawv tsis yog plaub hu rau txhua tus neeg SQL nqe lus