Cov txheej txheem:
Video: Kev siv Yes Tsis muaj teb yog dab tsi?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Cov Yog lawm - Tsis muaj teb yog siv los sau cov ntaub ntawv nrog tsuas yog a Yog lawm los yog Tsis muaj teb. Cov teb tshwm raws li daim ntawv teev npe poob rau ntawm daim ntaub. Cov lus teb yog khaws cia hauv database li 1 lossis 0 qhov twg 1 = Yog lawm thiab 0 = Tsis muaj . Thaum sau ntawv kos Code, siv (+) thiab (–) qhia yog thiab tsis muaj , raws.
Yog li, koj yuav ua li cas thiaj tsim tau Yes Tsis muaj teb nyob rau hauv kev nkag?
Format Property rau Yog lawm / Tsis muaj teb nyob rau hauv Access : Txheej txheem cej luam Txhawm rau teeb tsa hom cuab yeej rau Yog lawm / Tsis muaj teb nyob rau hauv Access , tsuas yog xaiv qhov laj thawj teb nyob rau hauv daim phiaj tabledesign. Tom qab ntawd nyem rau ntawm "Format" cov cuab yeej hauv teb cov khoom seem thiab xaiv ib qho kev xaiv los ntawm cov ntawv qhia zaub mov muaj.
Ib yam li ntawd, kuv yuav hloov hom ntawv li cas hauv kev nkag? Siv ib hom ntawv uas tau teem tseg ua ntej
- Qhib lub rooj hauv Design View.
- Nyob rau sab sauv ntawm daim phiaj tsim, xaiv Hnub/Timefield uas koj xav kom format.
- Hauv seem Field Properties, nyem qhov xub hauv lub thawv Formatproperty, thiab xaiv ib hom ntawv los ntawm daim ntawv teev npe.
Kuj paub, dab tsi yog tsis muaj cov ntaub ntawv hauv kev nkag?
Yog lawm / Tsis muaj . Cov Yog lawm / Tsis muaj hom ntaub ntawv hauv Access tsuas tuaj yeem yog ib qho ntawm 2 qhov tseem ceeb: -1 sawv cev rau True, lossis Yog lawm , los yog On. 0 sawv cev False, los yog Tsis muaj , orOff.
Koj yuav ntxiv ib pawg kev xaiv li cas hauv kev nkag mus?
Ntxiv ib qho kev xaiv tshiab rau ib pawg kev xaiv uas twb muaj lawm
- Ntawm Cov Tsim tab, hauv Pawg Tswj Xyuas, nyem lub cuab yeej rau hom kev tswj koj xav ntxiv (Check Box, Option Button, lossis Toggle Button).
- Txav tus pointer kom nws nyob rau hauv lub thav duab ntawm pawg xaiv.
- Nyem rau qhov chaw tswj hauv pab pawg.
Pom zoo:
Dab tsi ntawm cov hauv qab no yog qhov zoo ntawm kev siv cov khoom siv pom kev hauv kev hais lus?
Qhov txiaj ntsig tseem ceeb ntawm kev siv cov khoom siv pom hauv koj cov lus hais yog tias lawv ua kom cov neeg tuaj saib muaj kev txaus siab, hloov kev mloog ntawm tus neeg hais lus, thiab ua rau tus neeg hais lus muaj kev ntseeg siab ntau dua hauv kev nthuav qhia tag nrho
Dab tsi yog txheej txheem ntawm kev txhais ob lossis ntau txoj hauv kev hauv tib chav kawm uas muaj tib lub npe tab sis sib txawv tsis tshaj tawm?
Method overloading Tus kos npe ntawm ib txoj kev tsis suav nrog nws cov khoom xa rov qab los yog nws qhov kev pom los yog qhov kev zam uas nws yuav pov. Kev xyaum ntawm kev txhais ob lossis ntau txoj hauv kev hauv tib chav kawm uas qhia tib lub npe tab sis muaj qhov sib txawv yog hu ua cov txheej txheem overloading
Ib qho chaw tsis muaj zog puas tuaj yeem muaj qhov chaw tsis muaj zog?
Hom chaw tsis muaj zog muaj qee qhov yuam sij. Nco tseg- Lub koom haum tsis muaj zog ib txwm muaj kev koom tes tag nrho tab sis lub koomhaum muaj zog yuav tsis muaj tag nrho kev koom tes.Weak entity yog nyob ntawm qhov chaw muaj zog kom ntseeg tau tias muaj qhov tsis muaj zog. Zoo li lub koom haum muaj zog, qhov tsis muaj zog tsis muaj qhov tseem ceeb, Nws muaj feem cuam tshuam kev ntxub ntxaug
Puas muaj ib txoj hauv kev pov tseg qhov kev kuaj xyuas los ntawm txoj kev uas tsis muaj cov lus pov tseg?
9 Teb. Koj tuaj yeem pov cov kev txwv tsis raug txheeb xyuas yam tsis tas yuav tshaj tawm lawv yog tias koj xav tau tiag tiag. Unchecked kev zam txuas ntxiv RuntimeException. Throwables uas txuas ntxiv yuam kev tseem tsis tau txheeb xyuas, tab sis tsuas yog yuav tsum tau siv rau cov teeb meem loj tiag tiag (xws li invalid bytecode)
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