Video: Vim li cas cov ntaub ntawv tiaj tus tsis zoo dua li cov ntaub ntawv sib raug zoo?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Ib leeg tiaj tus -file table yog pab tau rau sau ib tug tsawg tus nqi ntawm cov ntaub ntawv. Tab sis ib tug loj tiaj tus - ntaub ntawv database tuaj yeem ua haujlwm tsis zoo vim nws siv ntau qhov chaw thiab nco tshaj qhov kev sib txheeb database . Nws kuj yuav tsum tau muab cov ntaub ntawv tshiab ntxiv txhua zaus koj nkag mus rau cov ntaub ntawv tshiab, whereas a kev sib txheeb database tsis.
Kuj nug, qhov txawv ntawm cov ntaub ntawv tiaj tus database thiab cov ntaub ntawv sib raug zoo yog dab tsi?
A flat file database khaws cov ntaub ntawv hauv a ib lub rooj qauv. A kev sib txheeb database siv ntau lub rooj sib dhos, cov ntaub ntawv sib txuas lus nruab nrab rooj.
Ib sab saum toj, dab tsi yog teeb meem nrog cov ntaub ntawv tiaj tus databases? Disadvantages ntawm flat file databases:
- Lub khoos phis tawj muaj ntau cov ntaub ntawv los nyeem, yog li nkag mus thiab tshawb nrhiav los ntawm lawv tuaj yeem qeeb.
- Cov ntaub ntawv yuav tsum tau rov ua dua thiab ua rau nkag mus rau qhov yuam kev thiab tsis sib xws.
- Cov ntaub ntawv loj tuaj yeem loj vim cov ntaub ntawv rov qab.
Tsis tas li ntawd, qhov zoo ntawm cov ntaub ntawv tiaj tus database yog dab tsi?
Flat File Database Advantages Qhov no pab tshawb nrhiav los ntawm cov ntaub ntawv rau cov ntaub ntawv. Cov ntaub ntawv tseem tuaj yeem raug txiav los ntawm qhov ntev. Yog tias cov ntaub ntawv luv luv, qee daim ntawv ntawm daim teb-padding tuaj yeem siv tau kom qhov ntev ntawm cov ntaub ntawv yog tib yam li cov tom ntej.
Nws txhais li cas rau flatten ib database?
flattening data hauv a 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.
Pom zoo:
Dab tsi yog qhov sib txawv ntawm cov ntaub ntawv sib sau ua ke thiab cov ntaub ntawv tsis sib xws?
Kev sib sau cov ntaub ntawv yog sau thiab sau cov ntaub ntawv; kom disaggregate cov ntaub ntawv yog rhuav tshem cov ntaub ntawv sib sau ua ke rau hauv cov khoom siv lossis cov ntaub ntawv me me
Vim li cas kev sib raug zoo algebra siv nyob rau hauv kev sib raug zoo database tswj?
RELATIONAL ALGEBRA yog ib hom lus nug uas siv dav heev. Nws sau cov xwm txheej ntawm kev sib raug zoo raws li kev tawm tswv yim thiab muab qhov tshwm sim ntawm kev sib raug zoo raws li cov zis. Nws siv ntau yam haujlwm los ua qhov haujlwm no. Relational algebra operations yog ua recursively ntawm kev sib raug zoo
Dab tsi yog qhov txawv ntawm kev sib raug zoo unary kev sib raug zoo binary thiab kev sib raug zoo ternary?
Kev sib raug zoo tsis sib xws yog thaum ob tus neeg koom hauv kev sib raug zoo yog tib lub koom haum. Piv txwv li: Cov ncauj lus yuav yog qhov yuav tsum tau ua ua ntej rau lwm yam kev kawm. Kev sib raug zoo ternary yog thaum peb lub koom haum koom nrog kev sib raug zoo
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 qhov txawv ntawm kev sib raug zoo thiab tsis muaj kev sib raug zoo databases?
Qhov sib txawv loj ntawm lawv yog li cas lawv tuav cov ntaub ntawv. Relational databases are structured.Non-relational databases are document-oriented. Qhov no hu ua cov ntaub ntawv hom cia tso cai ntau 'qeb' ntawm cov ntaub ntawv khaws cia hauv ib qho kev tsim lossis Cov Ntaub Ntawv