Video: Peb puas tuaj yeem siv cov lus npaj rau xaiv cov lus nug hauv Java?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Yuav ua li cas siv cov lus npaj rau xaiv cov lus nug hauv Java nrog MySQL? Tam sim no koj ua tau tso saib tag nrho cov ntaub ntawv ntawm lub rooj siv Java PreparedStatement . Koj xav tau siv txoj kev executeQuery().
Ib yam li ntawd, kev siv cov lus npaj yog dab tsi?
A npaj nqe lus yog ib qho feature siv los ua tib yam (lossis zoo sib xws) SQL nqe lus rov qab nrog high efficiency. Npaj nqe lus hauv paus ua haujlwm zoo li no: Npaj : Ib SQL nqe lus template yog tsim thiab xa mus rau lub database. Tej yam muaj nuj nqis tseem tsis tau teev tseg, hu ua parameters (labeled "?").
Ib yam li ntawd, peb puas tuaj yeem siv ib nqe lus npaj rau ntau cov lus nug? 5 Teb. Yog lawm koj ua tau rov- siv a Nqe lus (tshwj xeeb a Npaj Cov Lus Qhia ) thiab yuav tsum ua yog li feem ntau nrog JDBC. Nws yuav inefficient & phem style yog koj tsis tau rov- siv koj nqe lus thiab tam sim ntawd tsim ib tug zoo tib yam Nqe lus khoom.
Tsuas yog li ntawd, siv cov lus npaj hauv Java yog dab tsi?
Npaj Cov Lus Qhia hauv Java tso cai rau koj sau cov lus nug parameterized uas muab kev ua tau zoo dua Nqe lus chav kawm hauv Java . 2. Nyob rau hauv cov ntaub ntawv ntawm Npaj Cov Lus Qhia , Database siv ib qho uas twb tau sau ua ke thiab txhais cov phiaj xwm nkag, qhov no tso cai npaj nqe lus query kom khiav nrawm dua li cov lus nug ib txwm.
Yuav ua li cas koj rov qab siv cov lus uas tau npaj tseg?
Rov siv dua a Npaj Cov Lus Qhia Ib zaug ib Npaj Cov Lus Qhia yog npaj , nws tuaj yeem rov qab siv tau tom qab ua tiav. Koj rov siv dua a Npaj Cov Lus Qhia los ntawm kev teeb tsa qhov tseem ceeb tshiab rau cov kev txwv thiab tom qab ntawd rov ua dua. Ntawm no yog ib qho piv txwv yooj yooj yim: String sql = hloov cov neeg teeb tsa thawj lub npe =?, lub xeem =?
Pom zoo:
Peb puas tuaj yeem siv cov lus txuas ntxiv hauv kev hloov hauv C?
Yog, nws OK - nws zoo ib yam li siv nws hauv cov lus hais. Tau kawg, koj tsis tuaj yeem siv qhov tawg tawm ntawm lub voj los ntawm sab hauv lub hloov. Yog, txuas ntxiv yuav tsis quav ntsej los ntawm cov lus hloov pauv thiab yuav mus rau qhov xwm txheej ntawm lub voj yuav raug sim
Yuav ua li cas koj tuaj yeem txav qhov taw tes nrawm nrawm mus rau qhov pib ntawm cov lus nug cov lus nug?
T lossis F: Nias Ctrl + txoj cai xub yuam sij kom txav qhov taw tes rau qhov pib ntawm lo lus tom ntej
Peb puas tuaj yeem siv ua tiav tam sim rau cov lus xaiv?
Qhov kev pab cuam tuaj yeem siv EXECUTE IMMEDIATE. EXECUTE IMMEDIATE txhais ib lub voj voog xaiv los ua cov kab rov qab. Yog tias qhov kev xaiv rov qab tsuas yog ib kab, nws tsis tas yuav siv lub voj voog xaiv
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