Video: Hom ntaub ntawv twg tuaj yeem nkag mus tau?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Random thiab Sequential Describe Cov ntaub ntawv
A random - nkag tau cov ntaub ntawv enables koj rau nyeem lossis sau cov ntaub ntawv nyob qhov twg hauv ntaub ntawv . Nyob rau hauv sequential- nkag mus rau cov ntaub ntawv , koj ua tau tsuas yog nyeem thiab sau cov ntaub ntawv ua ntu zus, pib ntawm qhov pib ntawm qhov ntaub ntawv . Ob leeg hom ntaub ntawv muaj qhov zoo thiab qhov tsis zoo.
Tsis tas li ntawd, cov ntaub ntawv tau nkag mus li cas?
Random - access file yog ib lo lus siv los piav txog a ntaub ntawv los yog set ntawm cov ntaub ntawv uas yog nkag mus ncaj qha es tsis txhob xav kom lwm tus cov ntaub ntawv nyeem ua ntej. Khoos phis tawj hard drives nkag mus rau cov ntaub ntawv ncaj qha, qhov twg daim kab xev drives feem ntau nkag mus rau cov ntaub ntawv ua ntu zus.
Ib tug kuj nug, dab tsi yog hom ntaub ntawv nkag? Muaj peb txoj hauv kev nkag mus rau cov ntaub ntawv mus rau hauv lub computer: Sequential-Access, Direct Access, Index sequential Method.
- Sequential Access – Nws yog txoj kev nkag yooj yim tshaj plaws.
- Direct Access – Lwm txoj hauv kev yog txoj kev nkag ncaj qha los ntawm kev nkag mus rau tus txheeb ze.
- Index sequential method –
Ib yam li ntawd, dab tsi yog random access cia li?
Random - nkag mus nco (RAM) yog ib daim ntawv ntawm cov ntaub ntawv hauv computer khaws cia uas khaws cov ntaub ntawv thiab tshuab code tam sim no siv. A random - nkag tau lub cim xeeb ntaus ntawv tso cai rau cov ntaub ntawv los nyeem lossis sau yuav luag tib lub sijhawm tsis hais lub cev qhov chaw ntawm cov ntaub ntawv hauv nco.
Dab tsi yog ob qhov zoo ntawm cov ntaub ntawv nkag mus nkag tau?
Kuj tseem ceev dua random nkag . Ntawm qhov tod tes, random nkag cov ntaub ntawv muaj cov qhov zoo uas koj tuaj yeem tshawb xyuas los ntawm nws thiab nrhiav cov ntaub ntawv koj xav tau yooj yim dua (siv cov indexing piv txwv). Random Access Nco ( RAM ) hauv computer ua haujlwm zoo li ntawd.
Pom zoo:
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
Kuv puas tuaj yeem tau txais kuv cov ntaub ntawv rov qab tom qab hom ntawv?
Yog nws yog heev ua tau kom rov qab tau cov ntaub ntawv txawm tom qab ntaus ntawv yog formatted. Koj muaj peev xwm rov qab tau cov ntaub ntawv ploj los ntawm formatted hard disk, USB flash drive, nco daim card, Micro SD card thiab lwm yam yooj yim heev siv ib tug datarecovery software zoo li Wondershare Rov qab IT. Ua raws li cov kauj ruam no thiab rov qab tau cov ntaub ntawv ploj
Kuv tuaj yeem nrhiav TNS nkag ntawm cov ntaub ntawv nyob qhov twg?
Feem ntau, tnsnames. ora cov ntaub ntawv raug teeb tsa thaum koj nruab Oracle database. Los ntawm lub neej ntawd, cov tnsnames. ora cov ntaub ntawv nyob hauv ORACLE_HOME etworkadmin directory ntawm Windows thiab $ ORACLE_HOME/network/admin directory ntawm Linux/UNIX
Vim li cas kem taw qhia cov ntaub ntawv khaws cia ua cov ntaub ntawv nkag ntawm disks sai dua li kab qhia cov ntaub ntawv khaws cia?
Kem oriented databases (aka columnar databases) yog qhov tsim nyog rau kev ntsuas kev ua haujlwm ntau dua vim tias cov ntaub ntawv hom ntawv (kem hom) qiv nws tus kheej kom nrawm dua cov lus nug ua - scans, aggregation thiab lwm yam. Ntawm qhov tod tes, kab oriented databases khaws ib kab (thiab tag nrho nws. kab) contiguously
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