Funda ukuba njani Cima ilog ye-SQL ukugcina ikhompyuter yakho kunye nenkqubo yokusebenza elungiselelwe, lonke eli nqaku kunye nolwazi oluhle.
Lungiselela iqela lakho ngeyona ndlela ilungileyo
Kutheni le nto ucoca ilog ye-SQL?
Xa iikhompyuter zinenkqubo yokusebenza enezona mpawu ziphambili, oko kukuthi, imemori ye-RAM esezantsi, phakathi kwe-1GB okanye i-2GB, kunye neprosesa enendawo yokugcina esezantsi, ikhokelela kwinkqubo enezinto ezininzi kwimemori eqala ukunamathela.
Ilog ye-SQL igcwalisa imemori ngalo lonke ulwazi lwayo kwaye, ngenxa yoko, eli nani longezelelweyo leefayile longeza kwinto ecothisa inkqubo.
Ngokucima yonke loo rekhodi, inxenye yomsebenzi ekufuneka iqela liwenzile ikhutshwe, isenza inkqubo ihambelane ngakumbi.
Yintoni ilog yeSQL?
Yimisebenzi eyenziwa kwiseva ye-SQL. Umncedisi we-SQL ngabo balawula ukuhamba kweenkcukacha, oko kukuthi, kugcina lonke ulwazi olugcinwa yinkampani.
Imisebenzi eyenziwayo ziirekhodi zedatha elawulwa ziinkampani, nganye yezi rekhodi zenziwa kwaye zigcinwe kwiseva. Kukho iifayile ezahlukeneyo ezibekwe kwiseva ye-SQL, ukuxhasa konke oku kucinezelwe kwaye kubonisiwe njengeFayile yeLog, yahlulwe yaziFayile eziLungileyo zeLog okanye iiFayile zeNgcaciso.
Iifayile zelog ebonakalayo zenziwe ngokugqithileyo, kuba zisebenza ukugcina idatha kwiziko ledatha le-SQL kwaye, ke ngoko, ukugcinwa kugcwele ngakumbi, kuba yinto engekhoyo kwinkqubo. Inokujongwa ngokungqukuva, ukwahlulahlula kwezinye iifayile.
Iifayile zelog ebonakalayo zisebenzisa inkqubo yokunciphisa, oku kuthetha ukuba iifayile esele zisetyenzisiwe, zibekwa ekuphumleni kwaye ziyanqumama okomzuzwana. Emva koko, ifayile igqityiwe, isetyenziswa kwakhona kwaye inkqubo iyaqhubeka ngale ndlela, njengomjikelo.
Yintoni intengiselwano?
Intengiselwano ziifayile zolwazi ezinomxholo ovela kwiiseva ze-SQL. Ifayile yentengiselwano njengoko kuchaziwe, igcinwa kwifolda eyahlukileyo kwaye ilog eyahluliweyo iyenziwa.
Ifayile yokuthengiselana ibalulekile, kuba yiyo enceda ukwenza i-backups, kwimeko apho kukho into elahlekileyo kwiseva ye-SQL. Itshintshiwe nokuba ifayile isetyenziswa kangakanani, kuba icinezelwe ukuba inokwazi ngalo lonke ulwazi.
Amaxwebhu agcina iitafile, ezingabaququzeleli ezenziwe ngumsebenzisi, apho intsimi kunye neerekhodi zahlulwayo, uku-odola ulwazi ukuze lulungele umsebenzisi.
Intsimi ligama elisetyenziselwa ikholamu ephambili yolwazi, eyidatha ephambili eyahlula kwezinye iitafile. Iirekhodi yimigca eyahlukeneyo enokubhala itafile kwaye inolwazi lwamasimi asekwe ngumsebenzisi.
Isuswa nini ilog yokuthenga?
Ifayile yentengiselwano inokucinywa, xa ingenamsebenzi ukusombulula iserver kwaye ukuba ufuna ukucima kuphela ukuvula indawo kwinkqubo. Ukongeza, unokwenza ikopi yediski ekhuni okanye uyithumele kwiseva yewebhu apho banokugcina khona yonke into enxulumene neseva ye-SQL.
Kukho ulwazi olungenakupheliswa, kuba inkqubo ye-SQl iyayeka ukusebenza, ke ngoko, kufuneka silumke kwezi rejista ukuze zingachaphazeli inkqubo, nangona kunjalo, inkqubo enye iya kukuxelela ukuba le fayile iyasetyenziswa hayi susa.
Uyicima njani ilog ye-SQL?
Emva kokuchaza ukuba iirekhodi ze-SQL ziqulathe ntoni, ngoku singachaza indlela yokuyicima, sithathe onke amanyathelo afanelekileyo, njengoko sele kuchaziwe.
- Kuya kufuneka ungene kwiserver ye-SQL, apha sinokuhlela okanye senze utshintsho esicinga ukuba luyimfuneko kwiserver yethu.
- Sele iseva ye-SQL, DELETE uya kusetyenziswa uya kusetyenziswa, oqhele ukusebenza ukuphelisa naluphi na uhlobo lwenkqubo kwezinye iinkqubo. Ikwabizwa ngokuba ngumbuzo wokucima, isusa yonke idatha, kodwa ayiyiphelisi itafile.
- Iya kufakwa kunye NOMSEBENZI WOKUSUSA: "SUSA KWI-table_name WHERE column1 = 'value'" (Ngaphandle kwezicatshulwa.)
- Uya kungena "SUSA KULE tafile_name", eya kufumana itafile, equlathe irekhodi le-SQL, kwaye ke, lonke ulwazi.
- Umyalelo othi "APHO ikholam1 = 'ixabiso" »isetyenzisiwe, irekhodi elipheleleyo linokufumaneka ukuze likwazi ukuyiphelisa ngokuchanekileyo. I- "WHERE" ikuvumela ukuba ususe umda ekususweni kwengxelo, ehambelana neempawu esizicelayo.
- Kubalulekile ukuba uqaphele ukuba ukuba "APHO" ingabekwanga njengoko injalo okanye ingachazwanga njengoko kufanelekile, iirekhodi esinqwenela ukuzigcina zinokupheliswa. Uyilo lwetafile luya kugcinwa, kodwa aluyi kuba nalo naluphi na uhlobo lolwazi.
- Gcina ukhumbula emva kokubhala iikhowudi kunye neerejista, ukuba awuzukuphinda ufumane nantoni na esusiweyo, ke, jonga kakuhle ukuba akukho nto icinyiweyo iyimfuneko.
- Ngoku, igama letafile eza kucinywa liza kubekwa, umzekelo: "SUSA KWIINGOMA", ngaphandle kwalo naluphi na uhlobo lwempazamo.
- Emva koko, ikholamu eza kupheliswa iya kubhalwa, oko kukuthi, ukwahlulwa kwedatha esiyenzileyo etafileni, umzekelo: «APHO Rock = 'value'«.
- Okokugqibela, ixabiso elibhalisiweyo kudidi lwetafile libhaliwe, oko kukuthi, ukwahlulwa kwedatha eyenziweyo, umzekelo: «APHO Rock = 'jungle'«.
- Ingxelo egciniweyo ukucima iya kuba yile ilandelayo: «SUSA KWIINGOMA APHO IDwala = 'ixabiso'«. Amanyathelo afanayo aphindaphindwe kaninzi kangangoko kunokwenzeka ukuphelisa yonke idatha.
Ukuba ulithandile inqaku, ndiyakumema ukuba ufunde malunga: "Inkqubo yolawulo lwedatha yenzelwe ntoni?", isithuba esichazayo malunga nolu hlobo lwenkqubo, ndiyazi ukuba uya kuyithanda.