Video: Yuav ua li cas cov ntaub ntawv anomalies raug tshem tawm?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Yuav ua li cas zoo li anomalies raug tshem tawm ? Rooj ua tau muaj kev ntxig, hloov tshiab, lossis tshem tawm anomalies . Normalizing lub rooj qauv yuav txo cov cov ntaub ntawv redundance. Kev faib cov rooj sib faib cov ntaub ntawv rau hauv cov pab pawg sib raug zoo txo qis cov ntaub ntawv redundancy.
Tsis tas li ntawd, koj yuav tiv thaiv cov ntaub ntawv anomaly li cas?
Rau tiv thaiv Cov teeb meem no, koj tuaj yeem normalize cov qauv database. Normalization feem ntau entails faib ib lub rooj database rau hauv ob lub rooj yooj yim. Hloov kho anomalies yog li ntawd lub npe vim hais tias lawv yog generated los ntawm qhov sib ntxiv ntawm, hloov mus rau, los yog deletion ntawm cov ntaub ntawv los ntawm lub rooj database.
Tsis tas li ntawd, peb hom ntaub ntawv anomalies yog dab tsi? Muaj peb hom Cov Ntaub Ntawv Anomalies: Hloov tshiab Anomalies, Insertion Anomalies, thiab Kev tshem tawm Kev tsis sib haum xeeb.
Ua raws li qhov no saib, dab tsi yog cov ntaub ntawv redundancy nws tuaj yeem raug tshem tawm tag nrho?
Cov cov ntaub ntawv redundancy : Nws Tsis Tau tshem tawm tag nrho los ntawm lub database, txawm tias yuav tsum tau tswj redundancy Piv txwv li, xav txog kev sib raug zoo ntawm cov tub ntxhais kawm ntawv (S #, Sname, Course #, SubjectName, qhab nia) khaws cov qhab nia ntawm tus tub ntxhais kawm rau ib chav kawm uas muaj qee yam kev xaiv, tab sis txhua tus tub ntxhais kawm yuav tsum tsis txhob
Dab tsi yog deletion anomalies hauv DBMS?
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. Kom zam tau tej yam hloov tshiab los yog kev tshem tawm teeb meem, peb yuav tsum decompose thawj lub rooj rau hauv ob peb lub rooj me me uas txhua lub rooj muaj tsawg sib tshooj nrog lwm cov rooj.
Pom zoo:
Vim li cas cov ntaub ntawv tiaj tus tsis zoo dua li cov ntaub ntawv sib raug zoo?
Ib lub rooj ua ntaub ntawv tiaj tus yog qhov tseem ceeb rau kev sau cov ntaub ntawv tsawg. Tab sis cov ntaub ntawv loj loj tuaj yeem ua tsis tau raws li nws siv ntau qhov chaw thiab nco dua li cov ntaub ntawv sib txheeb. Nws kuj yuav tsum tau muab cov ntaub ntawv tshiab ntxiv txhua zaus koj nkag mus rau cov ntaub ntawv tshiab, qhov kev sib raug zoo database tsis
Dab tsi yog tus lej ncaj qha uas yuav tsum raug tshem tawm ntawm cov ntaub ntawv tshawb fawb kom ua raws li kev siv cov ntaub ntawv txwv?
Cov ntaub ntawv qhia ncaj qha hauv qab no yuav tsum raug tshem tawm rau PHI kom tsim nyog raws li cov ntaub ntawv txwv: (1) Cov npe; (2) Cov ntaub ntawv chaw nyob xa ntawv, tsis yog lub nroog lossis nroog, xeev, thiab ZIP code; (3) xov tooj; (4) fax xov tooj; (5) email chaw nyob; (6) social security naj npawb; (7) cov ntaub ntawv kho mob; (8) kev npaj kho mob
Thaum cov lus tau hla tawm cov ntaub ntawv kuaj xyuas feem ntau nthuav tawm cov ntawv sau thawj nrog kev pab ntawm dab tsi?
Infrared luminescence yog siv rau: Qhia tawm cov ntawv sau uas tau muab tshem tawm THIAB kuaj pom yog tias ob tus lej sib txawv tau siv rau hauv kev sau ntawv. Cov kws tshuaj xyuas cov ntaub ntawv feem ntau nthuav tawm cov ntawv sau thawj ntawm cov lus uas tau hla nrog kev pab ntawm: Infrared tawg
Vim li cas kem taw qhia cov ntaub ntawv khaws cia ua cov ntaub ntawv nkag ntawm disks sai dua li kab qhia cov ntaub ntawv khaws cia?
Kem oriented databases (aka columnar databases) yog qhov tsim nyog rau kev ntsuas kev ua haujlwm ntau dua vim tias cov ntaub ntawv hom ntawv (kem hom) qiv nws tus kheej kom nrawm dua cov lus nug ua - scans, aggregation thiab lwm yam. Ntawm qhov tod tes, kab oriented databases khaws ib kab (thiab tag nrho nws. kab) contiguously
Koj yuav tshem tawm OU li cas nrog kev tshem tawm tsis raug?
Coj mus rau OU uas koj xav rho tawm, txoj nyem rau ntawm nws thiab nyem rau ntawm Properties. Hauv Kev Tso Cai Nkag Nkag, yog tias qhov kev xaiv tsis lees txais nkag tau raug xaiv rau txhua tus, tshem nws. Nyem OK kom kaw qhov Advanced Security Settings. Nkag mus rau Cov Khoom tab thiab uncheck lub 'Protect from accidental deletion' checkbox