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Vim li cas xauv qhov tseem ceeb hauv SQL?
Vim li cas xauv qhov tseem ceeb hauv SQL?

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Video: Vim li cas xauv qhov tseem ceeb hauv SQL?
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SQL ntawv Server xauv yog cov qhov tseem ceeb ib feem ntawm qhov yuav tsum tau cais tawm thiab nws ua haujlwm rau xauv cov khoom cuam tshuam los ntawm kev lag luam. Thaum cov khoom muaj kaw , SQL ntawv Server yuav tiv thaiv lwm yam kev hloov pauv los ntawm kev hloov pauv ntawm cov ntaub ntawv khaws cia hauv cov khoom cuam tshuam los ntawm kev yuam xauv.

Hauv qhov no, SQL xauv yog dab tsi?

Xauv : Xauv yog ib tug mechanism los xyuas kom meej cov ntaub ntawv sib xws. SQL ntawv Server xauv khoom thaum qhov kev sib pauv pib. Thaum qhov kev hloov pauv tiav lawm, SQL ntawv Server tso tawm cov kaw khoom. Tshwj xeeb (X) Locks : Thaum no xauv hom tshwm sim, nws tshwm sim los tiv thaiv lwm yam kev hloov pauv lossis nkag mus rau a kaw khoom.

Kuj Paub, hom kev xauv hauv SQL Server yog dab tsi? SQL neeg rau zaub mov muaj ntau dua 20 ntau hom kev ntsuas phoo tab sis tam sim no cia peb tsom mus rau qhov tseem ceeb tshaj plaws.

  • Shared locks (S). Cov xauv no tau txais los ntawm cov neeg nyeem thaum nyeem cov haujlwm xws li SELECT.
  • Exclusive xauv (X).
  • Hloov tshiab xauv (U).
  • Lub hom phiaj xauv (IS, IX, IU, thiab lwm yam).

Tsis tas li ntawd, vim li cas peb thiaj li xauv lub database?

A database xauv yog siv rau “ xauv Qee cov ntaub ntawv hauv a database yog li ntawd ib leeg xwb database tus neeg siv / ntu tuaj yeem hloov kho cov ntaub ntawv tshwj xeeb. Yog li ntawd, database locks muaj rau tiv thaiv ob lossis ntau dua database cov neeg siv los ntawm kev hloov kho tib lub caij nyoog ntawm cov ntaub ntawv tib lub sijhawm.

Dab tsi yog qhov txawv ntawm cov xauv?

Txawm hais tias muaj ntau hom xauv, plaub feem ntau yog padlocks, deadbolts, knoblocks, thiab levers

  • Padlocks.
  • Deadbolts.
  • Knob Locks.
  • Lever Handle Locks.
  • Cam xauv.
  • Rim / Mortise Locks.
  • Euro Profile Lub tog raj kheej.
  • Phab ntsa Mounted Locks.

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