Cov txheej txheem:
Video: Dab tsi ua rau Rdbms kev sib raug zoo '?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
A kev sib txheeb database hais txog cov ntaub ntawv uas khaws cov ntaub ntawv hauv cov qauv tsim, siv cov kab thiab kab. Qhov no ua nws yooj yim mus nrhiav thiab nkag tau tej yam tseem ceeb nyob rau hauv lub database. Nws yog " kev sib raug zoo "vim cov txiaj ntsig hauv ib lub rooj muaj feem cuam tshuam rau ib leeg. Cov lus kuj tseem muaj feem cuam tshuam nrog cov ntxhuav.
Ib yam li ib tug yuav nug, qhov kev sib raug zoo txhais li cas hauv kev sib raug zoo database?
A kev sib txheeb database yog ib txheej ntawm cov lus piav qhia los ntawm qhov twg cov ntaub ntawv tuaj yeem nkag tau lossis rov tsim kho hauv ntau txoj kev sib txawv yam tsis tas yuav hloov kho lub database rooj. Tus txheej txheem neeg siv thiab applicationprogramming interface (API) ntawm a kev sib txheeb database yog tus qauv lus nug lus (SQL).
Ib tug kuj yuav nug, dab tsi yog lub hom phiaj ntawm kev sib raug zoo database? Yuav ua li cas Relational Databases Ua haujlwm. Cov haujlwm tseem ceeb ntawm DBMS yog nyeem (saib cov ntaub ntawv ntawm cov lus nug), tsim (ntxiv cov ntaub ntawv, rooj, kab, lossis kab), hloov tshiab (hloov cov ntaub ntawv, rooj, kab, lossis kab), thiab tshem tawm cov ntaub ntawv. Cov xwm txheej tuaj yeem raug ntxiv ua haujlwm ntxiv xws li hauv qab no: Saib cov ntaub ntawv uas ua tau raws li cov txheej txheem
Kuj kom paub yog, Rdbms cov ntsiab lus yog dab tsi?
RDBMS Cov Ntsiab Lus
- Rooj. Ib lub rooj yog ib phau ntawm cov ntaub ntawv sawv cev hauv kab thiab kab.
- Sau los yog Tuple. Txhua kab ntawm ib lub rooj yog hu ua cov ntaub ntawv.
- Field lossis Kem lub npe lossis tus cwj pwm. Cov lus saum toj no “STUDENT” muaj plaub qhov chaw (lossis tus cwj pwm): Student_Id, Student_Name, Student_Addr & Student_Age.
- Domain.
- Piv txwv thiab Schema.
- Cov yuam sij.
Excel puas yog cov ntaub ntawv sib raug zoo?
Excel cov lub koom haum qauv qiv nws tus kheej zoo li cas databases ua haujlwm. Ib daim ntawv qhia, ib leeg, yog a database , tab sis tsis yog a kev sib raug zoo ib. Cov Relationaldatabase yog ib qho kev sib txuas ntawm Master spreadsheet table and all of its Slave tables or spreadsheets.
Pom zoo:
Dab tsi yog qhov sib txawv ntawm kev sib txuas lus taw qhia thiab kev sib txuas tsis raug cai?
Qhov txawv: Kev sib txuas lus taw qhia thiab kev sib txuas tsis muaj kev sib txuas Kev sib txuas lus taw qhia kev sib txuas ua rau muaj kev sib txuas thiab xyuas seb cov lus puas tau txais lossis tsis tau thiab xa rov qab yog tias muaj qhov yuam kev tshwm sim, thaum qhov kev pabcuam tsis sib txuas tsis tau lees tias xa xov
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
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
Dab tsi yog qee qhov tsis zoo ntawm lub sijhawm stamping txoj hauv kev rau kev tswj hwm kev sib raug zoo?
Qhov tsis zoo ntawm lub sij hawm stamping mus kom ze yog tias txhua tus nqi khaws cia hauv cov ntaub ntawv yuav tsum muaj ob lub sij hawm thwj ntxiv: ib qho rau lub sijhawm kawg ntawm daim teb tau nyeem thiab ib qho rau qhov hloov tshiab kawg. Lub sij hawm stamping yog li ua rau kom nco xav tau thiab cov ntaub ntawv ua haujlwm nyiaj siv ua haujlwm