Video: Peb puas tuaj yeem siv Delete method hauv Varray?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Teb: Ntxiv nrog rau tus tsim hom Oracle kuj muab sau txoj kev rau siv nrog VARRAYS thiab nested rooj. Sau txoj kev ua tsis tau siv nyob rau hauv DML tab sis tsuas yog nyob rau hauv cov nqe lus txheej txheem. DELETE tshem tawm cov khoom teev tseg los ntawm ib lub rooj nested los yog tag nrho ntawm a. VARRAY.
Hauv qhov no, peb puas tuaj yeem tshem tawm cov ntsiab lus ntawm Varray hauv Oracle?
Txawm li cas los xij, koj tsis tuaj yeem hloov kho lossis rho tawm tus kheej varray ntsiab ncaj qha nrog SQL; koj yuav tsum xaiv cov varray los ntawm lub rooj, hloov nws hauv PL / SQL , tom qab ntawd hloov lub rooj kom suav nrog cov tshiab varray . Koj ua tau kuj ua qhov no nrog cov ntxhuav nested, tab sis cov ntxhuav nested muaj kev xaiv ntawm kev ua piecewise hloov tshiab thiab deletes.
Kuj Paub, Varray yog dab tsi? A VARRAY yog ib hom kev sau uas txhua lub ntsiab lus tau hais los ntawm tus lej zoo hu ua tus array qhov ntsuas. Qhov siab tshaj plaws cardinality ntawm lub VARRAY yog teev nyob rau hauv hom txhais. HOM IS VARRAY nqe lus yog siv los txhais a VARRAY hom kev sau.
Yog li ntawd, dab tsi yog qhov txawv ntawm trim delete collection method?
TRIM tshem tawm ib lossis ntau lub ntsiab lus los ntawm qhov kawg ntawm a sau , hos DELETE yuav tshem tawm cov khoom uas koj teev nyob qhov twg hauv kev sau . TRIM frees qhov chaw rau tshem tawm thiab DELETE tsis yog (tshwj tsis yog koj DELETE TAG NRHO cov ntsiab lus uas yog).
Cov txheej txheem sau se yog dab tsi?
A txoj kev sau yog ib tug built-in muaj nuj nqi los yog txheej txheem uas ua hauj lwm rau kev sau thiab hu ua siv dot notation. Koj tuaj yeem siv lub txoj kev EXISTS, COUNT, LIMIT, FIRST, LAST, PRIOR, NTXIV, EXTEND, TRIM, thiab DELETE los tswj kev sau nws qhov loj me tsis paub lossis txawv.
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