Video: Schema DBMS yog dab tsi?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Ib database schema yog lub cev pob txha uas sawv cev rau qhov kev xav pom ntawm tag nrho cov ntaub ntawv. Nws txhais li cas cov ntaub ntawv raug teeb tsa thiab kev sib raug zoo ntawm lawv li cas. Nws tsim tag nrho cov kev txwv uas yuav tsum tau siv rau ntawm cov ntaub ntawv.
Ib yam li ntawd, dab tsi yog schema hauv SQL nrog piv txwv?
Dab tsi yog a schema hauv SQL Server. A schema yog ib phau ntawm cov khoom siv database xws li cov ntxhuav, views, triggers, khaws cov txheej txheem, indexes, thiab lwm yam. Ntawm qhov tod tes, ib lub database yuav muaj ib los yog ntau yam. schemas . Rau piv txwv , hauv peb BikeStores qauv database, peb muaj ob schemas : kev muag khoom thiab kev tsim khoom.
Ib tug kuj yuav nug, dab tsi yog hom schema? Muaj ntau hom schemas , suav nrog cov khoom, tus neeg, kev sib raug zoo, kev tshwm sim, lub luag haujlwm, thiab tus kheej schemas . Schemas raug hloov kho thaum peb tau txais cov ntaub ntawv ntxiv. Cov txheej txheem no tuaj yeem tshwm sim los ntawm assimilation lossis kev pabcuam.
Tsis tas li ntawd, qhov laj thawj schema hauv DBMS yog dab tsi?
A logical cov ntaub ntawv qauv los yog logical schema yog cov qauv ntaub ntawv ntawm ib qho teeb meem tshwj xeeb uas tau hais tawm ntawm nws tus kheej ntawm ib qho kev tswj hwm cov khoom lag luam lossis kev siv thev naus laus zis (lub cev cov ntaub ntawv qauv) tab sis hais txog cov qauv ntaub ntawv xws li cov rooj sib tham thiab kab, cov chav kawm taw qhia, lossis XML cim npe.
Dab tsi yog schema thiab nws hom hauv DBMS?
DBMS Schema Kev txhais ntawm schema : Tsim lub database hu ua lub schema . Schema yog ntawm peb hom : Lub cev schema , logical schema thiab saib schema . Tsim database ntawm qib saib yog hu ua saib schema . Qhov no feem ntau piav qhia txog cov neeg siv kev sib cuam tshuam nrog cov txheej txheem database.
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