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Video: Dab tsi yog hom ntaub ntawv hauv SQL?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
SQL Data Type yog tus cwj pwm uas qhia txog qhov hom ntawm cov ntaub ntawv ntawm tej yam khoom. Txhua kem, sib txawv thiab nthuav qhia muaj qhov cuam tshuam hom ntaub ntawv hauv SQL . Koj tuaj yeem siv cov no hom ntaub ntawv thaum tsim koj lub rooj. Koj tuaj yeem xaiv ib hom ntaub ntawv rau ib kab lus raws li koj xav tau.
Ua li no, hom ntaub ntawv siv hauv SQL yog dab tsi?
SQL cov ntaub ntawv hom tuaj yeem muab faib ua ntau pawg hauv qab no
- Cov ntaub ntawv naj npawb xws li int, tinyint, bigint, ntab, tiag thiab lwm yam.
- Hnub thiab Lub Sijhawm cov ntaub ntawv xws li Hnub, Lub Sijhawm, Hnub Nyoog thiab lwm yam.
- Cim thiab hlua cov ntaub ntawv hom xws li char, varchar, ntawv nyeem thiab lwm yam.
Dab tsi yog hom ntaub ntawv hauv database? A hom ntaub ntawv database hais txog hom ntawv cov ntaub ntawv khaws cia uas tuaj yeem tuav qhov sib txawv hom los yog ntau yam ntawm cov nqi. Thaum cov khoos phis tawj khaws cia cov ntaub ntawv nyob rau hauv variables, txhua qhov sib txawv yuav tsum tau xaiv ib qho txawv hom ntaub ntawv . Qee yam hom ntaub ntawv muaj raws li nram no: integers, cim, hlua, floating point tooj thiab arrays.
Yog li ntawd, dab tsi yog hom ntaub ntawv hauv SQL Server?
A hom ntaub ntawv yog tus cwj pwm uas qhia txog qhov hom ntawm cov ntaub ntawv cov khoom ntawd khaws tau. Nws tuaj yeem yog tus lej, cim kab, nyiaj txiag, hnub thiab sijhawm, thiab lwm yam. SQL Server muab ib daim ntawv teev npe hom ntaub ntawv uas txhais tag nrho hom ntawm cov ntaub ntawv uas koj siv tau xws li, txhais ib kem lossis tshaj tawm a sib txawv.
Hom ntaub ntawv twg yog nyiaj hli?
Cov ntaub ntawv zauv feem ntau yog siv los khaws cov ntaub ntawv xws li nqe, nyiaj hli thiab lwm yam. Tso cai rau koj khaws tus nqi 1, 0, lossis NULL. Cov khw tus lej tus nqi hauv qhov ntau ntawm 0 txog 255. Cov khw muag khoom tus lej tus nqi hauv thaj tsam ntawm -32, 768 txog 32, 767.
Pom zoo:
Cov ntaub ntawv hom thiab cov qauv ntaub ntawv yog dab tsi?
Cov qauv ntaub ntawv yog ib txoj hauv kev piav qhia txog ib txoj hauv kev los npaj cov ntaub ntawv kom ua haujlwm andalogrithms tuaj yeem siv tau yooj yim dua. Ib hom ntaub ntawv piav qhia txog cov ntaub ntawv uas txhua tus sib koom ua ke. Piv txwv li tus lej cov ntaub ntawv hom piav qhia txhua tus lej uas lub khoos phis tawj tuaj yeem ua tau
Dab tsi yog hom ntaub ntawv thiab cov ntaub ntawv sib txawv?
Qee cov ntaub ntawv muaj xws li cov lej, cov lej ntab, cov cim, cov hlua, thiab cov arrays. Lawv kuj tseem yuav yog hom tshwj xeeb, xws li hnub tim, timestamps, booleanvalues, thiab varchar (tus cwj pwm sib txawv) cov qauv
Dab tsi yog lub hom phiaj ntawm delimiters nyob rau hauv cov ntawv sau npe ob hom ntawv cov ntaub ntawv delimiters?
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Dab tsi yog hom ntawv cov ntaub ntawv hauv SQL Server?
Nws yog Non-Unicode loj sib txawv ntev lub cim cov ntaub ntawv hom, uas tuaj yeem khaws qhov siab tshaj plaws ntawm 2147483647 Cov Cim Tsis-Unicode (piv txwv li qhov muaj peev xwm cia siab tshaj plaws yog: 2GB). Version ntawm Sql Server nyob rau hauv uas nws tau qhia? Cov ntaub ntawv hom yog tam sim no los ntawm cov qub versions ntawm Sql Server
Hom ntaub ntawv twg ntawm Hadoop tso cai rau columnar cov ntaub ntawv cia hom?
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