Video: Thaum twg kuv yuav tsum tsim ib qho index database?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Ib qhov ntsuas ntawm ib kem slows qhov kev ua tau zoo ntawm inserts, hloov tshiab thiab deletes. A database uas nquag hloov kho yuav tsum muaj tsawg dua indexes tshaj ib qho uas nyeem nkaus xwb. Kev xav txog qhov chaw Index siv qhov chaw nyob rau hauv lub database . Yog database qhov loj yog qhov kev txhawj xeeb tseem ceeb, koj yuav tsum tsim indexes me ntsis.
Tsis tas li ntawd, thaum twg koj yuav tsum tsim qhov ntsuas?
Index Cov Tables thiab cov kab kom raug Tsim ib qho index yog koj nquag xav rau retrieve tsawg dua li ntawm 15% ntawm cov kab hauv ib lub rooj loj. Qhov feem pua ntawm qhov pib no txawv heev, txawm li cas los xij, raws li rau tus txheeb ze ceev ntawm lub rooj scan thiab yuav ua li cas pawg cov ntaub ntawv kab yog hais txog cov qhov ntsuas tus yuam sij.
Tsis tas li ntawd, koj yuav ua li cas los tsim ib qho index hauv database? Sab saum toj 10 Cov kauj ruam los tsim cov txiaj ntsig Database Index
- Index los ntawm kev ua haujlwm, tsis yog los ntawm rooj.
- Index feem ntau siv cov lus nug hnyav.
- Index cov lus nug tseem ceeb.
- Index kom tsis txhob sorting (GROUP BY, ORDER BY)
- Tsim indexes rau uniqueness (PK, U)
- Tsim indexes rau txawv teb chaws yuam sij.
- Xav txog kev ntxiv kab rau qhov ntsuas tsuas yog nkag.
- Tsis txhob txwv tus naj npawb ntawm indexes arbitrarily.
Ib yam li ntawd, thaum twg koj yuav tsum tsis txhob indexing hauv database?
Index yuav tsum tsis txhob siv rau ntawm cov rooj me me. Index yuav tsum tsis txhob siv rau txhua kab uas rov qab muaj feem pua ntawm cov ntaub ntawv kab thaum siv los ua cov xwm txheej lim dej hauv cov lus nug nyob qhov twg. Piv txwv li, koj yuav tsis muaj qhov nkag rau lo lus "tus" lossis "thiab" hauv qhov qhov ntsuas ntawm ib phau ntawv.
Vim li cas peb thiaj tsim qhov Performance index ntawm cov ntxhuav?
Index yog siv los retrieve cov ntaub ntawv los ntawm database sai dua li lwm yam. Cov neeg siv tsis tuaj yeem pom cov indexes , lawv tsuas yog siv los txhawm rau tshawb nrhiav / nug. Nco tseg: Hloov kho a rooj nrog indexes yuav siv sij hawm ntau dua li hloov kho a rooj tsis muaj (vim lub indexes kuj xav tau kev hloov tshiab).
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