Qhov ntau dua ntawm qhov no ua rau kev nce qib ntawm cov ntaub ntawv. Yog li SQL queries tswj cov kab ntawm cov ntaub ntawv uas khaws cia hauv cov ntxhuav, thiab cov ntxhuav, dhau los, muaj nyob hauv ib lub database. … SQL yog hom lus tseem ceeb tshaj plaws uas siv los nkag rau hauv databases vim nws tuaj yeem ua haujlwm nrog txhua qhov database.
Lub hom phiaj ntawm SQL lus nug yog dab tsi?
SQL yog siv los sib txuas lus nrog database. Raws li ANSI (American National Standards Institute), nws yog hom lus rau kev sib raug zoo database tswj systems. Cov nqe lus SQL yog siv los ua cov haujlwm xws li hloov kho cov ntaub ntawv ntawm lub database, lossis khaws cov ntaub ntawv los ntawm database.
Qhov zoo ntawm cov lus nug yog dab tsi?
Siv cov lus nug SQL, tus neeg siv tuaj yeem khaws cov ntaub ntawv ntau ntawm cov ntaub ntawv los ntawm cov ntaub ntawv. Tsis xav tau coding. … Muaj qhov zoo hauv qab no ntawm SQL: Kev kub ceev. Siv cov lus nug SQL, tus neeg siv tuaj yeem tau txais cov ntaub ntawv ntau ntawm cov ntaub ntawv sai thiab zoo. …
Qhov txiaj ntsig ntawm kev siv SQL yog dab tsi?
Qee qhov zoo ntawm SQL yog raws li hauv qab no:
- Kev Tshawb Fawb nrawm dua - Cov ntaub ntawv ntau tau rov qab tau sai thiab ua tau zoo. …
- Tsis muaj Coding Skills - Rau kev khaws cov ntaub ntawv, tsis tas yuav muaj cov kab ntau ntawm cov lej. …
- Standardized Language – …
- Portable – …
- Sib tham lus - …
- Ntau cov ntaub ntawv saib -
Vim li cas nws tseem ceeb kom kawm SQL?
Kawm SQL tso cai rau koj los sau cov ntaub ntawv los ntawm ntau qhov chaw cov ntaub ntawv thiab hloov cov ntaub ntawv nyuaj rau kev txawj ntse. Ntau qhov dav, kev kawm tsim cov lus nug zoo SQL pab txhim kho cov neeg koom nrog kev txawj xav.
