Abo ukudala iindawo zabo ngesandla, ngaphandle koncedo abayili, okanye enze isicelo esiya banxibelelane inkonzo online, sijongene nengxaki yokugcina. Kwafa abantu, kuya kufuneka ukuba agcine zonke akhawunti yomsebenzisi kunye idatha yazo. Ngokusebenzisa ntoni oku konke ngayo? I SQL yam - yintoni na nokuba kutheni kubalulekile kakhulu efanelekileyo nqaku? Isibakala sokuba eli indlela yokufikelela data egcinwe kwi-website okanye iinkqubo abanofikelelo kwi-network ezahlukeneyo. Ngoko ke, kuyimfuneko ukwazi, I SQL yam - oko kukuthi, ziziphi iimpawu isicelo yayo zokuhlela.
Ingxaki yokwakhiwa kolwimi
Kodwa kuqala kufuneka bafunde indlela yonke iminxeba zenziwe ngento ethile. Kukho kakhulu inani elikhulu iindlela ukuba aququzelele uphendlo kwi data ezithile ezifumaneka kwinkqubo ulwazi. Enye indlela - into yokwakhiwa kolwimi (IsiNgesi shunqulelo SQL). It ikuvumela ukuba ukudala imibuzo ezimfutshane kukhethwa ulwazi oluyimfuneko. Kodwa unako ukusebenza kuphela amacwecwe emacala-mabini, wawabekayo phambili iqela lidla okwangoku. Ukuba usebenzisa kunyanzelekile ukucacisa umbuzo ulwimi ulwazi yakhiwe efunekayo yaye apho kufuneka ukuba zithathwe. Unga nokuba ukhankanye inani iimfuno ezongezelelweyo, uhlobo, ngokusekelwe kwi imeko ethile, okanye nje iqela. Kuba izixa e data amancinci kuyimfuneko iyafana.
Kutheni ufuna SQL yam?
Kwaye nale I SQL yam? Iyintoni na yonke loo nto? njani ukuqonda abafundi abaninzi ngokukhawuleza-uyiZisa, yinto ukwandiswa eyodwa yakhiwe ulwimi umbuzo. Kodwa ke kusetyenziswa phi? Into yokuba lo uguqulelo ekhethekileyo ukuze zisetyenziswe kwicandelo web lokuprograma. ulwimi Ordinary yokwakhiwa elide yenzelwe ukusebenza kwi computer, lo gama I SQL yam - kwi web-ingxenye.
Yintoni umahluko phakathi SQL yam and SQL
Nantso umahluko ziqwempu isicelo kunye umahluko eyinhloko. Kodwa kukho umahluko ezithile zenkqubo. Ngoko ke, ngaphambi kokuba usebenza kuvimba kusetyenziswa imibuzo I SQL yam, ufuna ukufikelela. Ewe, kwaye asebenze I SQL yam ngokwalo, ukuze oko ngokuzolileyo, akunakwenzeka. Ngoko ke, eziqhele ukusetyenziswa olongezelelweyo ulwimi lokuprograma omnye (ubukhulu becala PHP, nangona uyakwazi ukuhlangabezana abayili ukudala uxhulumaniso into ekuthiwa umncedisi we SQL).
Yintoni na isicelo?
Ngoku, xa uphendula umbuzo «SQL - oko kukuthi," ngaphambi kokuqhubeka kwiziphoso kunokwenzeka ukuba kwenzeka ngexesha ubhala iinkqubo, kufuneka siqwalasele izinto eziliqela: ukuba izicelo ezinjalo, iitafile zesiseko sedata neerekhodi. Masiqalise nge umbuzo: ukuba olufutshane Umxholo womyalezo khowudi kubonelelo data, kwaye kufuneka siqulathe ulwazi malunga apho ungajonga kubo, yaye amagama ngayo uphendlo iza kwenziwa. Ukuze, ukuba khangela apho, kufuneka kungabikho ngxaki. Kwaye yiloo nto amagama? Okanye kangakanani ungafumana i isitshixo? Ukwahlula iinkcukacha eziyimfuneko ukwenza isicelo unique ulwazi umgaqo. Baya inokufana inombolo okanye ezinye iinkcukacha. Kodwa kungcono basasebenzisa recognizers mvume.
Yintoni database?
na data amancinci agcinwe Apho I SQL yam ukufikelela? Kakade ke, kule iinkcukacha! Ngo I SQL yam, ukuba amabini mbini itafile equlethe ulwazi oluyimfuneko. Enanikade data ezichongwe yi ixabiso leyo isenokuba ngenxa lemizuzwana kuchazo lwexesha ledatha. Kwaye ulwazi kwisifundo ngasinye elitsha longezwa ukwenza umgca omtsha. inani elikhulu iitafile ukuze eziqulathwe kuvimba (akukho mda noko), kodwa database ichaphazela ubukhulu kunye nesantya data impendulo. Kodwa ngaphambi kokuba ukusebenza kunye database, kufuneka uqiniseke ukuba kukho inkxaso-software eyimfuneko kunye Umncedisi I SQL yam uya kuba nako ukuqala. Nangona yonke into apha kuxhomekeke kwiimeko ekuqaleni - ukuba usebenza ibamba kuhlawulwa, yonke into phantse ngaso. Kodwa ukuba wayeqeshe umncedisi, apho kufuneka ukusebenza ukususela ekuqaleni, ledatha I SQL yam, kwaye awukwazi ukusebenza kakuhle ngenxa yokuba akukho software evumela ukuba ukutolika iinkcukacha.
Yintoni itafile?
Table, njengoko sele kuchaziwe, esi sixhobo, leyo igcina idata kuyimfuneko. Into ngxenye? Xa ukwenza itheyibhile, qiniseka ukuba liliphi database yoba. A imeko apho kukho iitafile ngokwabo, kunokuba yingxaki - ngenxa yokuba uninzi izixhobo software zilungiselelwe ukuze baya kusebenzisana kunye neenkqubo ezithile.
Indlela ukukhangela idla itafile I SQL yam? Baye imihlathi ulwazi (lelithile uhlobo data) kunye uthotho apho egcinwe ulwazi kwisifundo ngasinye. Ngenxa zihloko kuphela - kukho isisifundo esitsha - ingeza umqolo omtsha (ngokususa luthe lwancothulwa). Kunye nemihlathi nzima kangako. Into yokuba njengomhalthi owodwa unokuba enye kuphela uhlobo data. Ngoko ke, ukuba umsebenzi wenziwe nge ikholam amanani, bhala awukwazi kuba kuso kwisicatshulwa. Lwenyoka iintlobo ezahlukeneyo, kukho abaliqela (malunga nama-30, wayesele ayithande inqaku eyahlukileyo).
Yintoni na irekhodi?
Kwaye wayi phambi kokugqithela kwiziphoso ezingenzeka ngethuba ukusetyenziswa I SQL yam, - ukurekhoda. irekhodi nganye (okanye umqolo) kufuneka into ebonakalisayo eyahlukileyo evumela ukuba ukujonga kuyo kwitheyibhile okanye iitafile ezininzi. Ezinokuba umda ubude bawo, kodwa ngenxa yokubukela lula ikwimo "manual" wabhenela ekuziseni ngohlobo "obuqhelekileyo". Umongo nokwehla enjalo kukuba ingxelo yaphukile ibe ziingceba eziliqela baze bafakwe neetafile ezahlukeneyo. Nangona eli candelo, kunokwenzeka ukuba kunye kubulelwe isazisi esisodwa. Sense actuation ifomu oluqhelekileyo amaqela ulwazi malunga izinto ngokusekelwe into eqhelekileyo. Umzekelo, ithala leencwadi anokwenziwa itafile "umntu", "Iincwadi" kunye "logs". Nangona xa kusenziwa lingaphunyezwa kunye etafileni enye kunye yokungena mnye, ukuba uya kuba yonke ingcaciso eyimfuneko.
iimpazamo engaba zikhona xa usebenzisa
Ngoku Ungaya kwi sifundo №2. Yeyiphi le nto kukho iimpazamo? Kwiimeko ezininzi, kuzo zonke ityala into zabantu. Oku kunokuba impazamo iyevakala ukuba kukhona ikhowudi gama kokuba imisiwe, okanye ngokungachanekanga zahlanganiswa umbuzo:
- Ukuba kukho ingxaki yokungena kwiziko ledatha, kufuneka ukhangele ingqibelelo wayo, kwakunye isicelo ifayile: oko kunikwa igama engalunganga, okanye igama sedata kuyo. Mhlawumbi, I SQL yam umyalezo wemposiso kwenzeka ngenxa yokunqongophala kokubeka isixhobo software, ekufuneka uqhagamshelwe kuvimba nokubonelela ukufunda ulwazi.
- Xa ucela data ukusuka kwizintlu kufuneka anyamekele ophezulu ezikumgangatho kokuhlaziya lwe data, kwakunye umva ukudluliselwa kolwazi ukusuka I SQL server kuwe. Njengoko sele kukhankanyiwe ngentla apha, njengoko umthetho, I SQL yam isetyenziswa ukuxhasa "abalamleli", ngoko ke akukho ngozi iya zihlolwe izixhobo iphutha ukuba ingaba wedatha efunekayo kufika kwaphela. Ukuba kuza, kodwa awukwazi ukuyisebenzisa kwabo - oko kuthetha ishishini zokucazulula idatha eyafunyanwa. Kulo mzekelo, kungakuhle ukuba uzame zonke iinketho kwabasebenzi, kuqalwa imiqulu lincinci lomsebenzi. Kufuneka kukhunjulwe, ingakumbi abo ekuqaleni nje ukuba ukuqonda zokuhlela ukuba lo mmandla apho yonke into isonjululwe yokusebenza kunye imposiso I SQL yam, uyakwazi ukususa wena, akuba wazama zonke iinketho kunokwenzeka.