Video: Dab tsi yog qhov ntxig thiab tshem tawm anomalies?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
A tshem tawm anomaly yog lub unintended poob ntawm cov ntaub ntawv vim kev tshem tawm ntawm lwm cov ntaub ntawv. Ib insertion anomaly yog qhov tsis muaj peev xwm ntxiv cov ntaub ntawv rau hauv database vim tsis muaj lwm cov ntaub ntawv.
Ib yam li ntawd, dab tsi yog deletion anomaly?
Deletion Anomaly . A tshem tawm anomaly tshwm sim thaum koj rho tawm cov ntaub ntawv uas tej zaum yuav muaj cov cwj pwm uas yuav tsum tsis txhob muab tshem tawm.
Ib sab saum toj no, dab tsi yog 3 anomalies? Muaj peb hom ntaub ntawv Kev tsis sib haum xeeb : Hloov tshiab Kev tsis sib haum xeeb , Insertion Kev tsis sib haum xeeb , thiab Deletion Kev tsis sib haum xeeb.
Tom qab ntawd, dab tsi yog qhov ntxig anomaly?
Ib Ntxig Anomaly tshwm sim thaum tej yam ntxwv ua tsis tau ntxig nyob rau hauv lub database tsis muaj lwm yam cwj pwm. Piv txwv li qhov no yog lub converse ntawm delete anomaly - Peb tsis tuaj yeem ntxiv chav kawm tshiab tshwj tsis yog tias peb muaj tsawg kawg yog ib tus tub ntxhais kawm cuv npe hauv chav kawm.
Dab tsi yog anomalies hauv DBMS?
Kev tsis sib haum xeeb yog cov teeb meem uas tuaj yeem tshwm sim hauv cov phiaj xwm tsis zoo, tsis yog cov ntaub ntawv tsis zoo uas txhua cov ntaub ntawv khaws cia hauv ib lub rooj (cov ntaub ntawv tiaj tus). Insertion Anomaly - Qhov xwm txheej ntawm cov ntaub ntawv yuav yog qhov uas nws tsis tuaj yeem ntxiv cov ntaub ntawv xav tau tshwj tsis yog lwm daim ntaub ntawv tseem tsis tau ntxiv.
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