Video: Dab tsi yog cov ntaub ntawv normalization hauv SQL?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Hauv luv luv, normalization yog ib txoj hauv kev los txhim kho cov ntaub ntawv hauv database. normalization entails npaj cov kab thiab cov ntxhuav ntawm ib lub database los xyuas kom meej tias lawv dependencies raug tswj kom zoo los ntawm database kev txwv tsis pub muaj. Nws feem ntau faib lub rooj loj rau hauv cov me me, yog li nws muaj txiaj ntsig zoo dua.
Kuj paub yog, nws txhais li cas rau normalize cov ntaub ntawv?
normalization feem ntau txhais tau tias txhawm rau ntsuas qhov sib txawv kom muaj qhov tseem ceeb ntawm 0 thiab 1, thaum kev hloov pauv hloov pauv cov ntaub ntawv kom muaj ib txhais tau tias ntawm xoom thiab tus qauv sib txawv ntawm 1. Qhov no standardization yog hu ua z-score, thiab cov ntaub ntawv cov ntsiab lus ua tau ua qauv nrog cov qauv hauv qab no: A z-score standardizes variables.
normalization ua li cas? ' normalization ' yog ib qho txheej txheem uas IBPS ua haujlwm txhawm rau txhawm rau ntsuas qhov ua tau zoo ntawm cov neeg sib tw raws li cov kev xeem zoo sib xws, tshwj xeeb tshaj yog qib nyuaj. Hauv paus, normalization aims los kho cov theem nyuaj nyob rau hauv ntau lub sij hawm ntawm kev xeem.
Ntxiv mus, dab tsi yog normalization nyob rau hauv database nrog piv txwv?
Database Normalization nrog Piv txwv : Database Normalization yog npaj cov ntaub ntawv uas tsis muaj teeb meem nyob rau hauv cov ntaub ntawv uas muaj qauv. Database normalization tsis muaj dab tsi tab sis kev teeb tsa cov rooj thiab cov kab ntawm cov ntxhuav hauv txoj hauv kev uas nws yuav tsum txo cov ntaub ntawv redundancy thiab complexity ntawm cov ntaub ntawv thiab txhim kho cov kev ncaj ncees ntawm cov ntaub ntawv.
Vim li cas normalization ua tiav?
Lub hom phiaj ntawm normalization yog khaws txhua kab ntawm cov ntaub ntawv ib zaug xwb, kom tsis txhob muaj cov ntaub ntawv anomalies. Cov ntaub ntawv anomaly tshwm sim thaum koj sim khaws cov ntaub ntawv hauv ob qhov chaw, thiab ib daim ntawv hloov pauv yam tsis muaj lwm daim ntawv hloov pauv hauv tib txoj kev.
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