Dab tsi yog nyeem uncommitted hauv SQL Server?
Dab tsi yog nyeem uncommitted hauv SQL Server?

Video: Dab tsi yog nyeem uncommitted hauv SQL Server?

Video: Dab tsi yog nyeem uncommitted hauv SQL Server?
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NYEEM TSIS TAU . Qhia meej tias cov lus tuaj yeem ua tau nyeem kab uas tau hloov kho los ntawm lwm yam kev lag luam tab sis tseem tsis tau cog lus. Transactions khiav ntawm lub NYEEM UNCOMMITTED qib tsis tso cov xauv sib koom los tiv thaiv lwm yam kev hloov pauv ntawm cov ntaub ntawv nyeem los ntawm kev lag luam tam sim no.

Hais txog qhov no, nyeem dab tsi tau cog lus hauv SQL Server?

NYEEM COMMITTED yog lub default isolation theem rau SQL Server . Nws tiv thaiv qias neeg nyeem los ntawm kev qhia tias cov lus tsis tuaj yeem nyeem cov ntaub ntawv muaj nuj nqis uas tau hloov kho tab sis tseem tsis tau cog lus los ntawm lwm yam kev lag luam. Kev hloov pauv siv cov ntaub ntawv kab ntawv uas muaj nyob thaum qhov kev sib pauv pib.

Kuj Paub, dab tsi yog phantom nyeem? A phantom nyeem tshwm sim thaum, nyob rau hauv lub chav kawm ntawm ib tug lw, ob queries zoo tib yam raug tua, thiab sau cov kab rov qab los ntawm cov lus nug thib ob yog txawv ntawm thawj. Cov piv txwv yooj yim: Tus neeg siv A khiav tib cov lus nug ob zaug.

Nyob rau hauv no txoj kev, yog nyeem uncommitted tib yam li Nolock?

Qhov tsuas yog qhov sib txawv ntawm ob yog qhov nyeem - tsis kam lees Kev rho tawm theem txiav txim siab qhov ntsuas phoo mechanism rau tag nrho kev sib txuas thiab cov nolock lub rooj hint txiav txim lub xauv mechanism rau lub rooj uas koj muab cov lus qhia rau. Tsis muaj qhov sib txawv ntawm lawv cov haujlwm, zoo li lwm tus tau hais.

Dab tsi yog nyeem tsis tau hauv db2?

Los ntawm V4, DB 2 tau muab nyeem -los ntawm cov xauv, tseem paub tias " qias neeg nyeem "los yog" tsis kam lees nyeem ,”los pab kov yeej cov teeb meem concurrency. Thaum siv ib tsis kam lees nyeem ib daim ntawv thov kev pab cuam tuaj yeem nyeem cov ntaub ntawv uas tau hloov pauv, tab sis tseem tsis tau cog lus tseg.

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