2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Kev sib raug zoo . Hauv UML modeling, ib kev sib raug zoo yog a kev sib raug zoo nruab nrab ntawm ob lub ntsiab lus, uas ib qho qauv (tus neeg siv khoom) paub txog tus cwj pwm uas lwm tus qauv (tus neeg muag khoom) qhia. Ntau tus neeg tuaj yeem paub txog tus cwj pwm ntawm ib tus neeg muag khoom.
Ua raws li qhov no hauv kev xav, kev sib raug zoo hauv UML yog dab tsi?
Hauv UML modeling, ib kev sib raug zoo yog kev sib txuas ntawm ob lossis ntau dua UML qauv cov ntsiab lus uas ntxiv cov ntaub ntawv semantic rau tus qauv. Ib qho abstraction kev sib raug zoo yog ib qho kev vam khom ntawm cov qauv qauv uas sawv cev rau tib lub tswv yim ntawm ntau theem ntawm abstraction los yog los ntawm cov kev xav sib txawv.
Tsis tas li, puas yog kev sib raug zoo hauv UML cov duab kos duab? Kev sib raug zoo hauv kab kos duab . Hauv UML , a kev sib raug zoo yog kev sib txuas ntawm cov qauv tsim. A UML kev sib raug zoo yog ib hom qauv qauv uas ntxiv semantics rau tus qauv los ntawm kev txhais cov qauv thiab tus cwj pwm ntawm cov qauv qauv. Kev sib raug zoo hauv kab kos duab qhia kev sib cuam tshuam ntawm chav kawm thiab classifiers
Kuj Paub, yog dab tsi realization Ooad?
Kev paub . Kev paub tiag yog ib qho kev sib raug zoo ntawm chav kawm blueprint thiab cov khoom uas muaj nws cov ntsiab lus ntawm theem kev siv. Cov khoom no tau hais kom paub txog cov chav kawm dav dav. Hauv lwm lo lus, koj tuaj yeem nkag siab qhov no raws li kev sib raug zoo ntawm qhov interface thiab cov chav kawm siv.
UML daim duab yog dab tsi?
A UML daim duab yog a daim duab raws li qhov UML (Unified Modeling Language) nrog rau lub hom phiaj ntawm kev pom kev sawv cev rau lub system nrog rau nws cov neeg ua yeeb yam tseem ceeb, lub luag haujlwm, kev ua, cov khoom qub lossis cov chav kawm, txhawm rau nkag siab zoo dua, hloov kho, tswj, lossis cov ntaub ntawv hais txog lub system.
Pom zoo:
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 kev sib tshuam hauv kev sib raug zoo algebra?
INTERSECTION kev khiav hauj lwm nyob rau hauv RELATIONAL ALGEBRA. Kev sib tshuam ntawm teeb A thiab B = A ∩ B = {1, 6} Cov ntsiab lus uas muaj nyob rau hauv ob qho tib si A thiab B yuav tsuas muaj nyob rau hauv lub teeb tau los ntawm kev sib tshuam ntawm A thiab B
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