Cov txheej txheem:
Video: Dab tsi yog hom ntaub ntawv raw hauv Oracle?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Txhais: Hauv Oracle PL/SQL , RAW yog a hom ntaub ntawv siv los khaws binary cov ntaub ntawv , los yog cov ntaub ntawv uas yog byte taw qhia (piv txwv li, duab lossis cov ntaub ntawv audio). Ib qho tseem ceeb tshaj plaws yuav tsum nco ntsoov txog RAW data yog tias nws tsuas tuaj yeem nug lossis ntxig; RAW data tsis tau manipulated. Oracle Cov ntaub ntawv hom: RAW.
Tsis tas li ntawd, ntev npaum li cas datatype hauv Oracle?
LONG RAW yog ib Oracle cov ntaub ntawv hom rau khaws cov ntaub ntawv binary ntawm qhov sib txawv ntawm qhov ntev mus txog 2 Gigabytes ntev. Nco ntsoov tias ib lub rooj tsuas muaj ib qho xwb LONG RAW kem.
Ib tug kuj yuav nug, dab tsi yog tus lej datatype hauv Oracle? Taw qhia rau Oracle NUMBER cov ntaub ntawv hom Cov Oracle NUMBER cov ntaub ntawv hom yog siv los khaws cov lej muaj txiaj ntsig uas tuaj yeem ua tsis zoo lossis zoo. Cov hauv qab no qhia txog cov syntax ntawm lub NUMBER hom ntaub ntawv : 1. NUMBER [(precision [, scale])] Cov Oracle NUMBER cov ntaub ntawv hom muaj precision thiab scale.
Ntawm no, hom ntaub ntawv siv hauv Oracle yog dab tsi?
Oracle muab cov ntaub ntawv hauv qab no built-in:
- tus cwj pwm datatypes. CHAR. NCHAR. VARCHAR2 thiab VARCHAR. NRHA 2. CLOB. NCLOB. LONG.
- NUMBER datatype.
- DATE datatype.
- binary datatypes. BLOB. BFILE. RAW. LONG RAW.
Dab tsi yog timestamp datatype hauv Oracle?
Cov TIMESTAMP datatype yog qhov txuas ntxiv ntawm DATE hom ntaub ntawv . Nws khaws cov xyoo, hli, hnub, teev, feeb, thiab qhov tseem ceeb thib ob. Nws kuj tseem khaws cov ntu ntu ntu, uas tsis khaws cia los ntawm DATE hom ntaub ntawv . Oracle Database SQL Reference rau cov lus qhia ntxiv txog cov TIMESTAMP datatype.
Pom zoo:
Cov ntaub ntawv hom thiab cov qauv ntaub ntawv yog dab tsi?
Cov qauv ntaub ntawv yog ib txoj hauv kev piav qhia txog ib txoj hauv kev los npaj cov ntaub ntawv kom ua haujlwm andalogrithms tuaj yeem siv tau yooj yim dua. Ib hom ntaub ntawv piav qhia txog cov ntaub ntawv uas txhua tus sib koom ua ke. Piv txwv li tus lej cov ntaub ntawv hom piav qhia txhua tus lej uas lub khoos phis tawj tuaj yeem ua tau
Cov ntaub ntawv hom ntawv hauv PostgreSQL yog dab tsi?
Cov ntawv nyeem cov ntaub ntawv tuaj yeem khaws ib txoj hlua nrog ntev ntev. Yog tias koj tsis qhia meej tus lej n rau hom varchar cov ntaub ntawv, nws coj zoo li cov ntawv nyeem cov ntaub ntawv. Kev ua tau zoo ntawm varchar (tsis muaj n) thiab cov ntawv nyeem yog tib yam
Dab tsi yog hom ntaub ntawv thiab cov ntaub ntawv sib txawv?
Qee cov ntaub ntawv muaj xws li cov lej, cov lej ntab, cov cim, cov hlua, thiab cov arrays. Lawv kuj tseem yuav yog hom tshwj xeeb, xws li hnub tim, timestamps, booleanvalues, thiab varchar (tus cwj pwm sib txawv) cov qauv
Dab tsi yog lub hom phiaj ntawm delimiters nyob rau hauv cov ntawv sau npe ob hom ntawv cov ntaub ntawv delimiters?
Cov ntaub ntawv delimited yog cov ntawv nyeem siv los khaws cov ntaub ntawv, uas txhua kab sawv cev rau ib phau ntawv, tuam txhab, lossis lwm yam, thiab txhua kab muaj cov teb sib cais los ntawm tus lej
Hom ntaub ntawv twg ntawm Hadoop tso cai rau columnar cov ntaub ntawv cia hom?
Columnar ntaub ntawv tawm tswv yim (Parquet, RFile) Qhov tseeb hotness nyob rau hauv cov ntaub ntawv tawm tswv yim rau Hadoop iscolumnar cov ntaub ntawv cia. Yeej qhov no txhais tau hais tias tsis yog cia li khaws cov kab ntawm cov ntaub ntawv nyob ib sab rau ib leeg koj kuj khaws cov kab ntawv nyob ib sab. Yog li datasets tau muab faib ua ob qho tib si horizontally thiab vertically