Cov txheej txheem:
Video: Cov indexes khaws cia hauv MySQL li cas?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
MySQL muaj khw tus indexes txoj kev no vim cov ntaub ntawv yog khaws cia nyob rau hauv qhov tseem ceeb random kev txiav txim. Nrog pawg indexes , lub ntsiab tseem ceeb thiab cov ntaub ntawv nws tus kheej yog "clustered" ua ke, thiab cov ntaub ntawv yog tag nrho khaws cia nyob rau hauv lub hauv paus ntsiab lus. InnoDB siv clustered indexes.
Tsis tas li lo lus nug yog, qhov twg yog qhov ntsuas ntsuas khaws cia hauv MySQL?
Feem ntau MySQL indexes (PIB TSEEM CEEB, UNIQUE, INDEX , thiab FULLTEXT) yog khaws cia hauv B-ntoo. Kev zam yog qhov ntawd indexes ntawm spatial cov ntaub ntawv hom siv R-ntoo, thiab cov lus MEMORY kuj txhawb hash indexes.
Ib tug kuj yuav nug, database indexes khaws cia li cas? Nws yog cov txheej txheem txheej txheem cov ntaub ntawv uas yog siv los nrhiav thiab nkag mus rau cov ntaub ntawv hauv a database . Index yog tsim siv ob peb database kab. Cov nqi no yog khaws cia nyob rau hauv kev txiav txim kom cov ntaub ntawv sib xws tuaj yeem nkag tau sai. Nco tseg: Cov ntaub ntawv yuav los yog tsis yog khaws cia nyob rau hauv kev txiav txim.
Ua raws li qhov no saib, indexes ua haujlwm li cas hauv MySQL?
Index yog siv los nrhiav kab nrog cov kab ke tshwj xeeb sai sai. Tsis muaj ib qhov ntsuas , MySQL yuav tsum pib nrog thawj kab thiab tom qab ntawd nyeem tag nrho cov lus kom pom cov kab uas cuam tshuam. Lub rooj loj dua, tus nqi no ntau dua.
Dab tsi yog hom indexes hauv MySQL?
Tsib Hom Indexs
- Ib qho kev ntsuas tshwj xeeb yog ib qho uas tag nrho cov kab ke yuav tsum yog qhov tshwj xeeb.
- Tus yuam sij tseem ceeb yog qhov ntsuas tshwj xeeb uas tsis muaj nqi tuaj yeem yog NULL.
- Ib qho yooj yim, tsis tu ncua, lossis qhov ntsuas ib txwm yog qhov ntsuas qhov ntsuas qhov tseem ceeb tsis tas yuav yog qhov tshwj xeeb thiab lawv tuaj yeem ua NULL.
Pom zoo:
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