Peb puas tuaj yeem tsim qhov ntsuas ntawm kab virtual hauv Oracle?
Peb puas tuaj yeem tsim qhov ntsuas ntawm kab virtual hauv Oracle?

Video: Peb puas tuaj yeem tsim qhov ntsuas ntawm kab virtual hauv Oracle?

Video: Peb puas tuaj yeem tsim qhov ntsuas ntawm kab virtual hauv Oracle?
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Virtual kab tuaj yeem siv nyob rau hauv qhov chaw nyob clause ntawm UPDATE thiab DELETE nqe lus tab sis lawv ua tau 'tsis raug hloov kho los ntawm DML. Lawv ua tau siv los ua tus yuam sij muab faib hauv virtual kab raws li partitioning. Indexs tau raug tsim rau lawv. Raws li koj tej zaum yuav tau kwv yees, oracle yuav tsim muaj nuj nqi raws li indexes raws li peb tsim ntawm cov rooj qub.

Khaws qhov no hauv kev txiav txim siab, ntawm kab ntawv twg koj yuav tsum tsim qhov ntsuas hauv Oracle?

Indexs muab kev nkag tau sai rau cov ntaub ntawv rau kev ua haujlwm uas rov qab ib feem me me ntawm lub rooj kab . Feem ntau, koj yuav tsum tsim qhov Performance index ntawm ib kem hauv ib qho ntawm cov xwm txheej hauv qab no: Kab lus nug ntau zaus. Ib qho kev txwv kev ncaj ncees muaj nyob rau ntawm kab.

Tsis tas li ntawd, kuv puas tuaj yeem tsim qhov Performance index ntawm saib hauv Oracle? Indexing thiab Saib . Oracle SQL qauv ua tsis txhawb tsim indexes ntawm views . Yog koj xav tau qhov ntsuas cov ntaub ntawv uas nws cov ntsiab lus nyob rau hauv cov rooj sib txawv, koj tuaj yeem tsim cov ntaub ntawv khaws cia nyiam siv USER_DATASTORE khoom.

Ib yam li ntawd, dab tsi yog ib kem virtual hauv Oracle?

Taw qhia rau lub Oracle virtual kab A virtual kab yog lub rooj kem uas nws qhov tseem ceeb yog xam tau siv lwm yam kem qhov tseem ceeb, lossis lwm qhov kev txiav txim siab. Ntawm no yog cov syntax ntawm a virtual kab : 1. column_name [data_type] [GENERATED ALWAYS] AS (expression) [ VIRTUAL ]

Peb puas tuaj yeem tsim qhov ntsuas ntawm lub hauv paus tseem ceeb hauv Oracle?

Los ntawm default, lub CREATE INDEX nqe lus tsim ib tug btree qhov ntsuas . Thaum koj tsim ib lub rooj tshiab nrog a thawj tus yuam sij , Oracle cia li tsim ib qho tshiab qhov ntsuas rau cov thawj cov kab ke . Tsis zoo li lwm cov database systems, Oracle tsis tau tsim ib qhov ntsuas rau txawv teb chaws cov kab tseem ceeb.

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