Video: Cov ntaub ntawv nquag txhais li cas?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Active Record yog lub M hauv MVC - tus qauv - uas yog cov txheej txheej ntawm lub luag hauj lwm rau sawv cev ua lag luam cov ntaub ntawv thiab logic. Active Cov Ntaub Ntawv txhawb kev tsim thiab siv cov khoom lag luam uas nws cov ntaub ntawv yuav tsum tau khaws cia tsis tu ncua rau hauv cov ntaub ntawv.
Ib yam li ntawd, tib neeg nug, ua li cas cov ntaub ntawv nquag ua haujlwm?
Nws yeej txhais tau tias Active Cov Ntaub Ntawv siv cov ntaub ntawv uas tau muab khaws cia rau hauv lub rooj database siv kab thiab kab, uas yuav tsum tau hloov kho lossis rov qab los ntawm kev sau SQL nqe lus (yog tias koj siv SQL database), thiab nws cia koj cuam tshuam nrog cov ntaub ntawv zoo li nws yog ib txwm muaj. Ruby khoom.
Ib sab saum toj no, Active Cov Ntaub Ntawv hauv Rails yog dab tsi? Rails Active Cov Ntaub Ntawv muab ib qho kev sib txuas thiab khi ntawm cov ntxhuav hauv cov ntaub ntawv sib raug zoo thiab Ruby program code uas tswj cov ntaub ntawv cov ntaub ntawv . Txhua Active Cov Ntaub Ntawv object muaj CRUD (Tsim, Nyeem, Hloov Kho, thiab Rho tawm) txoj hauv kev rau kev nkag mus rau cov ntaub ntawv.
Ib sab ntawm qhov no, puas yog cov ntaub ntawv nquag ua ORM?
Active Cov Ntaub Ntawv yog ib qho kev coj ua ntawm qhov kev sib txheeb ze ze ( ORM ) qauv los ntawm tib lub npe piav qhia los ntawm Martin Fowler: "Ib yam khoom uas qhwv ib kab hauv lub rooj database lossis saib, encapsulates cov ntaub ntawv nkag, thiab ntxiv cov logic ntawm cov ntaub ntawv ntawd."
Dab tsi yog cov ntaub ntawv nquag hauv PHP?
php ib - activerecord yog lub tsev qiv ntawv qhib ORM raws li cov ActiveRecord qauv. Nws lub hom phiaj ua kom yooj yim rau kev sib cuam tshuam nrog koj cov ntaub ntawv thiab tshem tawm cov haujlwm ntawm tes sau SQL rau kev ua haujlwm. Tsis zoo li lwm yam ORMs, koj tsis tas yuav siv cov code generators los yog tuav cov ntaub ntawv rau koj cov ntxhuav.
Pom zoo:
Vim li cas cov ntaub ntawv tiaj tus tsis zoo dua li cov ntaub ntawv sib raug zoo?
Ib lub rooj ua ntaub ntawv tiaj tus yog qhov tseem ceeb rau kev sau cov ntaub ntawv tsawg. Tab sis cov ntaub ntawv loj loj tuaj yeem ua tsis tau raws li nws siv ntau qhov chaw thiab nco dua li cov ntaub ntawv sib txheeb. Nws kuj yuav tsum tau muab cov ntaub ntawv tshiab ntxiv txhua zaus koj nkag mus rau cov ntaub ntawv tshiab, qhov kev sib raug zoo database tsis
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)
Kuv yuav ua li cas thiaj tsim tau ZIP cov ntaub ntawv nrog ntau cov ntaub ntawv?
Muab ob peb cov ntaub ntawv mus rau hauv ib qho zippedfolder kom yooj yim sib faib ib pawg ntawm cov ntaub ntawv. Nrhiav cov ntaub ntawv lossis nplaub tshev uas koj xav zip. Nias thiab tuav (lossis right-click) cov ntaub ntawv lossis ntawv tais ceev tseg, xaiv (lossis taw tes rau) Xa mus rau, thiab tom qab ntawd xaiv Compressed (zipped) folder
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
Dab tsi yog cov teeb meem ntawm kev tswj cov ntaub ntawv hauv cov ntaub ntawv ib txwm muaj?
Nyob rau tib lub sijhawm, qhov kev tswj hwm cov ntaub ntawv ib puag ncig tsim teeb meem xws li cov ntaub ntawv rov ua dua thiab tsis sib xws, cov kev pab cuam-cov ntaub ntawv dependence, inflexibility, tsis muaj kev ruaj ntseg, thiab tsis muaj cov ntaub ntawv sib qhia thiab muaj