Video: Dab tsi yog qhov kev txwv sib tshooj?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Overlap Constraint -Ib overlap txwv txiav txim seb puas los yog tsis yog ob subclasses muaj peev xwm muaj tib lub koom haum.
Tib neeg kuj nug, dab tsi yog overlapping hauv database?
Kev sib tshooj subtype: Tsis yog tshwj xeeb subsets ntawm lub supertype entity set yog hu ua sib tshooj subtype. Txhua qhov chaw piv txwv ntawm supertype tuaj yeem tshwm sim tsawg kawg ib hom subtype. Txoj cai no tau teev nrog tsab ntawv "o" hauv lub voj voog yog txuas ntawm tus supertype thiab nws cov subtypes.
Tsis tas li ntawd, Disjointness txwv yog dab tsi? A txwv hais txog generalization hierarchies. A disjointness txwv txhais tau hais tias cov subtypes tsis sib koom ib qho chaw. Hauv lwm lo lus, kev sib tshuam ntawm pawg ntawm cov koom haum hauv cov subtypes yog khoob.
Ua raws li qhov kev pom no, dab tsi yog qhov tsis sib xws thiab kev txwv sib tshooj?
Nyob rau hauv ib tug disjointness tsim txwv , ib qho chaw tuaj yeem koom tsis tau ntau tshaj ib qho chaw qis qis. Hauv sib tshooj generalizations, tib lub koom haum tej zaum yuav muaj ntau tshaj ib tug qis-theem chaw teeb. Piv txwv li, nyob rau hauv cov neeg ua hauj lwm-paub pawg neeg ua hauj lwm piv txwv ntawm phau ntawv, ib tug thawj coj yuav koom nrog ntau tshaj ib pab neeg ua hauj lwm.
Dab tsi yog qhov sib tshooj subtype?
Overlapping subtypes yog subtypes uas muaj cov tsis tshwj xeeb subsets ntawm lub supertype chaw teeb; uas yog, txhua qhov chaw piv txwv ntawm tus supertype yuav tshwm sim hauv ntau dua ib qho subtype . Piv txwv li, nyob rau hauv ib cheeb tsam tsev kawm ntawv, ib tug neeg tej zaum yuav yog ib tug neeg ua hauj lwm los yog ib tug me nyuam kawm ntawv los yog ob qho tib si.
Pom zoo:
Dab tsi yog qhov sib txawv ntawm qhov kev txiav tawm thiab qhov kev sib cav Ampliative?
Yog hais tias tus arguer ntseeg hais tias qhov tseeb ntawm qhov chaw yeej tsim qhov tseeb ntawm qhov xaus, ces qhov kev sib cav yog deductive. Yog hais tias tus arguer ntseeg hais tias qhov tseeb ntawm qhov chaw muab tsuas yog vim li cas zoo los ntseeg qhov xaus yog tej zaum muaj tseeb, ces qhov kev sib cav yog inductive
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 qub txeeg qub teg Dab tsi yog qhov sib txawv ntawm qhov qub txeeg qub teg piav nrog piv txwv?
Inheritance yog ib txoj hauv kev kom tau txais cov yam ntxwv thiab kev coj cwj pwm ntawm ib chav kawm los ntawm lwm chav kawm. Cov chav kawm uas cov tswv cuab tau txais qub txeeg qub teg yog hu ua chav kawm hauv paus, thiab chav kawm uas tau txais cov tswv cuab tam sim no hu ua chav derived. Inheritance siv IS-A kev sib raug zoo
Dab tsi yog qhov sib txawv tseem ceeb ntawm kev sib txuas lus tsis sib xws thiab kev sib txuas lus taw qhia?
1. Hauv kev sib txuas lus tsis muaj kev sib txuas lus tsis tas yuav tsim kev sib txuas ntawm qhov chaw (sender) thiab qhov chaw (receiver). Tab sis nyob rau hauv kev sib txuas-taw qhia kev sib txuas lus kev sib txuas lus yuav tsum tau tsim ua ntej hloov cov ntaub ntawv
Dab tsi yog qhov kev txwv kev ncaj ncees piav qhia txog kev ncaj ncees lossis kev txwv txawv teb chaws?
Kev lees paub ncaj ncees xav kom tus yuam sij txawv teb chaws yuav tsum muaj tus yuam sij tseem ceeb sib xws lossis nws yuav tsum yog null. Qhov kev txwv no tau teev tseg ntawm ob lub rooj (niam txiv thiab menyuam); nws tuav cov ntawv xov xwm ntawm kab hauv cov rooj no. Nws txhais tau hais tias kev siv los ntawm kab hauv ib lub rooj mus rau lwm lub rooj yuav tsum siv tau