Dab tsi yog qhov ua rau thiab cov txheej txheem khaws cia hauv SQL?
Dab tsi yog qhov ua rau thiab cov txheej txheem khaws cia hauv SQL?

Video: Dab tsi yog qhov ua rau thiab cov txheej txheem khaws cia hauv SQL?

Video: Dab tsi yog qhov ua rau thiab cov txheej txheem khaws cia hauv SQL?
Video: Tshuaj theem vim li cas thiaj tau nqi ?/ Siv kho mob dab tsi?/paris polyphylla use for? 2024, Kaum ib hlis
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Cov txheej txheem khaws cia yog tus neeg siv tau teev tseg ntawm cov lej sau rau hauv lub zos version ntawm PL / SQL, uas yuav rov qab tau tus nqi (ua kom nws ua haujlwm) uas tau hu los ntawm kev hu nws meej. Ib qho txiaj ntsig yog cov txheej txheem khaws cia uas khiav tau thaum muaj ntau yam xwm txheej tshwm sim (xws li hloov tshiab , ntxig , rho tawm ).

Hauv qhov no, dab tsi yog qhov txawv ntawm qhov tshwm sim thiab cov txheej txheem khaws cia?

Peb tuaj yeem ua tiav a khaws cov txheej txheem thaum twg peb xav nrog kev pab los ntawm exec hais kom ua, tab sis a ua rau tsuas tuaj yeem raug tua thaum twg ib qho kev tshwm sim (ntxig, rho tawm, thiab hloov tshiab) raug rho tawm haujlwm ntawm lub rooj uas ua rau yog txhais. Cov txheej txheem khaws cia tuaj yeem rov qab muaj nuj nqis tab sis a ua rau tsis tuaj yeem rov qab tus nqi.

Ib yam li ntawd, qhov txheej txheem khaws cia yog dab tsi thiab nws siv li cas? Cov txheej txheem khaws cia yog siv los khaws cov ntaub ntawv, hloov kho cov ntaub ntawv, thiab tshem tawm cov ntaub ntawv hauv cov ntaub ntawv database. Koj tsis tas yuav sau tag nrho SQL ntawv txib txhua zaus koj xav ntxig, hloov tshiab lossis rho tawm cov ntaub ntawv hauv ib qho SQL ntawv database. Cov txheej txheem khaws cia yog cov txheej txheem ua ntej ntawm ib lossis ntau dua SQL ntawv cov lus uas ua qee yam haujlwm tshwj xeeb.

Ua raws li qhov kev pom no, peb puas tuaj yeem siv qhov cuam tshuam hauv cov txheej txheem khaws cia?

Koj hu tsis tau Ua rau los ntawm Cov txheej txheem khaws cia , as Ua rau yog tsim rau ntawm rooj thiab raug rho tawm implicitly. Tab sis koj ua tau hu khaws cov txheej txheem mus los ntawm ua rau , mas ua nco ntsoov nws yuav tsum tsis txhob recursive.

Cov txheej txheem khaws cia hauv DBMS yog dab tsi?

A khaws cov txheej txheem yog ib txheej ntawm Structured Query Language (SQL) nqe lus nrog rau lub npe, uas yog khaws cia hauv kev sib raug zoo kev tswj database system ua ib pab pawg, yog li nws tuaj yeem rov siv dua thiab sib koom los ntawm ntau qhov kev pab cuam.

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