I-SQL isetshenziselwa ukwabelana nokuphatha idatha, ikakhulukazi idatha etholakala kuma-system management management database - idatha ihlelwe ngamatafula, futhi amafayela amaningi, ngalinye equkethe amatafula wedatha, angathintana ndawonye ngensimu evamile.
Ukusebenzisa i-SQL, ungacela (funa ulwazi kusuka kumininingwane yolwazi), ubuyekeze futhi uhlele kabusha idatha, futhi udale futhi uguqule isakhiwo (isakhiwo) sesistimu yedatha, uphinde ulawule ukufinyelela kwedatha. Isofthiwe evamile esetshenziselwa amaseva we-SQL ihlanganisa i-Microsoft Access, i-MySQL, ne-Oracle.
Umlando we-SQL
Ngo-1969, umcwaningi we-IBM u-Edgar F. Codd wachaza imodeli yezinhlelo zokuxhumana, okwaba yisisekelo sokuthuthukisa ulimi lwe-SQL. Ngokumane nje, imodeli ye-database ehlobeneyo inezici ezivamile (noma "ukhiye") ohlotshaniswa nedatha ehlukahlukene. Isibonelo igama lomsebenzisi elihlotshaniswa kokubili igama lakho langempela nenombolo yocingo.
Eminyakeni embalwa kamuva, i-IBM yaqala ukusebenza ngolimi olusha lwezinhlelo zokuphathwa kwedatha yezokuxhumana ngokusekelwe ekutholeni kweCodd. Ulimi lwalokuqala lwalubizwa nge-SEQUEL, noma uLimi Oluhlelekile Lwemibuzo YesiNgisi. Le phrojekthi, ebizwa ngokuthi i-System / R, yahamba ngokusebenzisa ukuqaliswa okuncane nokubuyekezwa, futhi igama lolimi lushintshwa izikhathi ezimbalwa ngaphambi kokuthi kuthiwa yi-SQL.
Ngemva kokuqala ukuhlola ku-SQL ngo-1978, IBM yaqala ukuthuthukisa imikhiqizo yezohwebo, kuhlanganise neSQL / DS (1981) noDB2 (1983). Abanye abathengisi balandela okufanayo, bememezela ngeminikelo yabo ye-SQL esekelwe ekuhwebeni. Lezi zihlanganisa u-Oracle, owakhipha umkhiqizo wawo wokuqala ngo-1979, kanye no-Sybase no-Ingres.
Ukufunda i-SQL
I-SQL kulula kubaqalayo ukuthi bafunde kunokuba bakhethe izilimi zokuhlela njengeJava, C ++, PHP noma C #.
Uma ufuna ukufunda i-SQL, kodwa unemvelaphi encane kakhulu yokuhlela, ungazuza ngokuyizama usebenzisa enye yezinsiza ezingezansi, bese uthatha ukudibela okujulile ngekolishi esemthethweni noma ekolishi yomphakathi ekolishi. Uma kungenjalo, ungasebenzisa ama-tutorials amaningi e-inthanethi mahhala noma izifundo ezikhokhelwayo zokufunda ibanga.
Nazi ezinye zezibonelo zama-tutorials mahhala:
I-W3Schools SQL Tutorial
I-SQLcourse.com (isifundo se-SQL esethula)
I-Codecademy inehlelo lokufunda lwe-SQL, kanye nenkambo ephakeme ekuhlaziyeni amamethrikhi webhizinisi le-SQL
Uma unesithakazelo kwizifundo zokufunda ibanga elikhokhelwayo, sincoma i-International Webmasters Association's (IWA) Isingeniso ku-SQL (Ukusebenzisa Ukufinyelela) noma Isingeniso SQL (Ukusebenzisa i-MySQL).
Ngithathe izifundo ze-IWA ngaphambili. I-SQL enamasonto amane kuphela, kodwa ihlelwe kakhulu kunezifundiswa zokuzifundela ngoba izifundo ziholwa ngabafundisi futhi zihilela ukuqeda izabelo ezithile kanye ngesonto. Ungamangala ukuthi ungakufunda kanjani kuleso sikhathi esifushane.
Izincwadi eziwusizo kwi-SQL yabaqalayo zihlanganisa:
I-SQL: Umhlahlandlela Wokuqala
I-SQL ku-Nutshell
Hlola umtapo wakho wendawo ukuze ubone ukuthi bathwala lezi zincwadi noma ezinye izincwadi ze-SQL ezethula.
Amakhono we-SQL ayadingeka
Njengoba kushiwo ngaphambili, cishe wonke umuntu udinga umuntu onolwazi lwe-SQL enhlanganweni yakhe.
Ngokusho kukaGooroo, imisebenzi engu-50 705 yanyatheliswa ngo-2015 eyayidinga ulwazi lwe-SQL, futhi umholo wesikhashana wesikhundla esidinga ulwazi lwe-SQL ngu-$ 81,632.
Nazi ezinye izinhlobo zezikhundla ezidinga amakhono eSQL: