Cov txheej txheem:
Video: Nws txhais li cas rau flatten cov ntaub ntawv?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
flattening tus cov ntaub ntawv hauv database txhais tau tias tias koj khaws cia rau hauv ib lossis ob peb lub rooj uas muaj tag nrho cov ntaub ntawv, nrog rau kev tswj hwm me me ntawm cov qauv. Hauv database lingo, uas yog hu ua denormalized schema.
Kuj paub yog, ua li cas koj flatten cov ntaub ntawv?
Cov ntsiab lus
- Xaiv qhov ntau yam uas koj xav kom flatten - feem ntau, ib kem ntawm cov ntawv sau.
- Qhia qhov khoob ntawm lub hlwb nkaus xwb - ntaus F5 (GoTo) thiab xaiv Tshwj xeeb> Blanks.
- Ntaus qhov sib npaug (=) thiab tom qab ntawd Up Arrow kom nkag mus rau cov qauv nrog cov xov tooj ncaj qha siv rau thawj cov ntaub ntawv sau npe.
Cov ntaub ntawv tiaj tus yog dab tsi? A tiaj tus database yog ib qho yooj yim database system uas txhua lub database yog sawv cev raws li ib lub rooj nyob rau hauv uas tag nrho cov ntaub ntawv khaws cia raws li ib kab ntawm cov ntaub ntawv , uas yog cais los ntawm delimiters xws li tabs lossis commas. Lub rooj feem ntau yog khaws cia thiab lub cev sawv cev ua cov ntawv nyeem yooj yim.
Ib yam li ntawd ib tug yuav nug, nws txhais li cas rau flatten ib daim ntawv?
Flattening ib daim ntawv hauv computer science txhais tau tias tshem tawm ib qho zes cov npe los ntawm kev muab lawv ua cov ntsiab lus, recursively, nyob rau hauv qhov kev txiav txim lawv tau teev tseg. Piv txwv li, Python nested lis [1, 2, 3, [4, 5, 6], [7], [8, [9, 10], 11], 12] yuav ua flattened mus rau hauv lis ntawm cov ntsiab lus 1 txog 12, suav nrog.
Dab tsi yog denormalization hauv database nrog piv txwv?
Denormalization hauv Databases . Denormalization yog a database optimization txheej txheem nyob rau hauv uas peb ntxiv redundant cov ntaub ntawv rau ib los yog ntau lub rooj. Rau piv txwv , nyob rau hauv ib tug normalized database , tej zaum peb yuav muaj ib lub rooj kawm ntawv thiab ib lub rooj Xib Fwb. Txhua qhov kev nkag hauv Chav Kawm yuav khaws tus xibfwb qhia ntawv rau Chav Kawm tab sis tsis yog tus xibfwb qhia npe.
Pom zoo:
Kuv yuav hloov cov ntaub ntawv tab delimited rau cov ntaub ntawv csv li cas?
Mus rau cov ntawv qhia zaub mov, xaiv 'OpenCSVTab-Delimited File' (lossis tsuas yog nias Ctrl + O), thiab tom qab ntawd los ntawm lub thawv qhib, xaiv cov ntaub ntawv tab-delimited qhib. Koj tuaj yeem luam cov tab-delimited txoj hlua mus rau clipboard thiab tom qab ntawd siv 'Qhib Cov Ntawv Hauv Cov Ntawv Teev Npe' xaiv (Ctrl + F7)
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
Yuav ua li cas rau txim nyob rau hauv Is Nrias teb rau nyiag computer cov ntaub ntawv cov cuab tam los yog tej software qhov chaw code los ntawm ib tug neeg lub koom haum los yog los ntawm lwm yam txhais tau tias?
Kev piav qhia: Kev rau txim hauv Is Nrias teb rau kev nyiag cov ntaub ntawv hauv computer, cov khoom muaj nqis lossis ib qho software cov cai los ntawm ib lub koom haum, ib tus neeg, lossis los ntawm lwm txoj kev yog raug kaw 3 xyoo thiab raug nplua ntawm Rs. 500,000
Vim li cas cov ntaub ntawv zoo tseem ceeb heev rau kev sau cov ntaub ntawv txheeb cais?
Cov ntaub ntawv muaj txiaj ntsig zoo yuav ua kom muaj txiaj ntsig ntau dua hauv kev tsav lub tuam txhab kev vam meej vim yog kev vam khom ntawm qhov tseeb-raws li kev txiav txim siab, tsis yog kev coj cwj pwm lossis tib neeg kev xav. Ua kom tiav: Xyuas kom tsis muaj qhov khoob ntawm cov ntaub ntawv los ntawm qhov yuav tsum tau sau thiab qhov twg tau sau tiag
Nws txhais li cas rau cov ntaub ntawv theem?
Ib cheeb tsam staging, lossis thaj chaw tsaws, yog thaj chaw nruab nrab cia siv rau kev ua cov ntaub ntawv thaum lub sijhawm rho tawm, hloov pauv thiab thauj khoom (ETL) txheej txheem. Cov ntaub ntawv staging cheeb tsam zaum ntawm cov ntaub ntawv qhov chaw thiab cov ntaub ntawv lub hom phiaj (s), uas feem ntau cov ntaub ntawv warehouses, cov ntaub ntawv marts, los yog lwm yam ntaub ntawv repositories