Video: Puas yog hom kev sib raug zoo hauv Java?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Hom Kev Sib Raug Zoo . Raws li kev rov siv cov ntaub ntawv cov tswv cuab los ntawm ib chav kawm mus rau lwm chav kawm hauv JAVA peb muaj peb hom kev sib raug zoo . Lawv yog-a kev sib raug zoo , muaj-a kev sib raug zoo thiab siv-a kev sib raug zoo . Siv-a kev sib raug zoo yog ib txoj hauv kev uas ib chav kawm siv ib yam khoom ntawm lwm chav kawm.
Xav txog qhov no, puas muaj kev sib raug zoo java?
Hauv Java , a Has-A kev sib raug zoo tseem hu ua muaj pes tsawg leeg. Hauv Java , a Has-A kev sib raug zoo tsuas yog txhais tau tias ib qho piv txwv ntawm ib chav kawm muaj ib qho kev siv rau ib qho piv txwv ntawm lwm chav kawm lossis lwm qhov piv txwv ntawm tib chav kawm. Piv txwv li, ib lub tsheb muaj ib engine, aub muaj ib tail.
Ib sab saum toj no, puas muaj kev siv kev sib raug zoo? Txhua qhov chaw koj pom cov lus tseem ceeb txuas ntxiv lossis siv lo lus tseem ceeb hauv cov lus tshaj tawm hauv chav kawm, tom qab ntawd chav kawm no tau hais tias muaj IS-A kev sib raug zoo . YOG -A Kev sib raug zoo : Composition( YOG -A) tsuas yog txhais tau tias siv cov piv txwv hloov pauv uas yog siv rau lwm yam khoom. Piv txwv li Maruti muaj Cav, los yog Lub Tsev muaj Chav dej.
Kuj nug, qhov txawv ntawm IS A thiab muaj kev sib raug zoo hauv Java yog dab tsi?
Hauv OOP, IS - A kev sib raug zoo yog qub txeeg qub teg. Qhov no txhais tau tias, cov chav kawm me nyuam yog ib hom niam txiv chav kawm. A HAS-A kev sib raug zoo yog dynamic (khiav lub sij hawm) khi thaum qub txeeg qub teg yog ib qho zoo li qub (sib sau lub sij hawm) khi. Yog tias koj tsuas yog xav rov siv cov cai thiab koj paub tias ob qho tib si tsis zoo siv cov khoom sib xyaw.
ISA kev sib raug zoo yog dab tsi?
ISA kev sib raug zoo . Koj tuaj yeem qhia meej tias ib chav kawm yog subclass ntawm lwm tus los ntawm kev tsim ib qho Isa kev sib raug zoo . Raws li lub neej ntawd, ib Isa node tsuas qhia tau hais tias ib pawg ntawm cov khoom yog subclasses ntawm lwm yam khoom, tab sis tsis muaj dab tsi ntxiv.
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