Dab tsi yog lub rooj sib tham hauv kev sib raug zoo?
Dab tsi yog lub rooj sib tham hauv kev sib raug zoo?

Video: Dab tsi yog lub rooj sib tham hauv kev sib raug zoo?

Video: Dab tsi yog lub rooj sib tham hauv kev sib raug zoo?
Video: yog hmoov dab tsi. Zoo Xyooj (cover) 2024, Kaum ib hlis
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Ib associative rooj yog qhov tsis tseem ceeb rooj uas nws lub ntsiab tseem ceeb yog txhua tus yuam sij txawv teb chaws. Vim cov rooj sib tham qauv ntshiab kev sib raug zoo es tsis yog cov koom haum, cov kab ntawm ib qho associative rooj tsis sawv cev rau cov koom haum. Xwb, lawv piav txog tus kev sib raug zoo ntawm cov koom haum rooj sawv cev.

Tsis tas li ntawd, dab tsi yog qhov piv txwv ntawm kev sib koom ua ke?

Ib koom haum koom haum yog lub rooj uas koom nrog ob lub rooj sib tham hauv ntau qhov kev sib raug zoo. Ib koom nrog kev sib raug zoo attribute yog tus cwj pwm ntawm tus koom haum koom haum uas tshwm sim vim muaj ntau rau ntau txoj kev sib raug zoo. Ntawm no yog ib qho piv txwv . Nws yog tus cwj pwm ntawm lub koom haum.

Tsis tas li ntawd, thaum twg kev sib raug zoo yuav tsum tau hloov mus rau ib qho chaw koom nrog? 1 Teb. Associative cov koom haum yog siv thaum koj xav tau a kev sib raug zoo los koom nrog a kev sib raug zoo . Rau ib txwm ntau-rau-ntau kev sib raug zoo nruab nrab ntawm Tub Ntxhais Kawm thiab Chav Kawm, peb tsuas yog siv pob zeb diamond xwb. Txawm li cas los xij, yog tias peb xav koom nrog Kev Sau Npe nrog Xib Fwb, peb ua tau tig Enrollment rau hauv ib qho koom haum koom haum.

Ib yam li ntawd, koj tuaj yeem nug, dab tsi yog hom koom haum koom nrog?

Ib koom haum koom haum yog ib lo lus siv nyob rau hauv relational thiab qhov chaw - kev sib raug zoo txoj kev xav. Cov ntaub ntawv kev sib raug zoo yuav tsum tau ua raws li kev sib raug zoo ntawm lub hauv paus (los yog lub hauv paus rooj) los daws ntau qhov kev sib raug zoo. Ib qho kev sib raug zoo sawv cev rau qhov no zoo ntawm qhov chaw hu ua, tsis raws cai, ib koom nrog rooj.

Kev sib raug zoo 1 N yog dab tsi?

1 -rau-ntau, los yog 1 : N kev sib raug zoo , yog siv thaum koj tsim ib kev sib raug zoo nruab nrab ntawm ob qhov chaw uas muaj ntau cov ntaub ntawv los ntawm ib qhov chaw cuam tshuam nrog ib qho ntaub ntawv los ntawm lwm qhov chaw. Hauv layman cov ntsiab lus, qhov no txhais tau hais tias thaum koj muaj niam txiv (los yog thawj) qhov chaw thiab ntau yam (los yog menyuam) cov koom haum.

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