Ngaba ufunda ngabaphathi beenkcukacha? Kwimeko apho, kufuneka wazise malunga ne- Iindidi zedatha kwi-MySQL, yenye yezona zilungileyo kwaye zisetyenziswa kakhulu emhlabeni.Ungaphuthelwa lithuba!
Iindidi zedatha kwi-MySQL
Ngalo lonke ixesha sifuna ukwenza itafile enokusetyenziselwa ukugcina idatha yesicelo, kufuneka sazi indlela yokuchonga ukuba loluphi uhlobo lwedatha olusincedayo ekugcineni yonke into esiyifunayo. Singakhetha phakathi kwezinto ezintathu: idatha yamanani, imitya (alphanumeric), kunye nemihla namaxesha.
Kule mihlaba yeetafile ze-MYSQL sinethuba lokukhetha phakathi kweentlobo ezintathu zomxholo, kwaye nangona kubonakala kucacile, misela ukuba siyithumele phi idatha yethu, siluhlobo luni lweqela eligciniweyo, apha sinomzekelo wokuzibeka kwimeko: ewe sidinga umhlaba apho sinokugcina khona ubudala bomntu, iya kuba yintsimi yedatha yamanani.
Kodwa ngaphambi kokuba ndiqhubeke ndichaze, uyazi ukuba yintoni i-MySQL? Yaziwa njengomnye wabaphathi beenkcukacha zemithombo evulekileyo kwihlabathi liphela. Ukuze sibe nombono wokuba ithandwa kangakanani, siza kukuxelela ukuba: I-WordPress ngumphathi weentlobo ezahlukeneyo zomxholo, okhoyo ukususela ngo-2003, kwaye malunga nama-55% ukuya kuma-60% amaphepha ewebhu exist, zenziwa umbulelo koku, kwaye isebenzisa i-MySQL njengesiseko sedatha, ke oku kungqina ukuba kunokuba luncedo kangakanani kunye nomda ekuyo.
I-MySQL yeyenkampani yeOracle Corporation, eyayiphethe ukuyithenga ngo-2010. Lo mphathi unokusetyenziswa okuninzi, okufana: nokuziqhelanisa, ukwenza ufakelo, ukulungisa amaphepha ewebhu, ukufunda idatha, phakathi kwabanye.
Lo mqhubi unokukhutshelwa ngokulula kwaye uneenguqulelo ezininzi ngokuxhomekeke kwiWindows oyisebenzisayo, ngendlela efanayo, kulula kakhulu ukuyifaka.
Uninzi lwabaqhubi beenkcukacha zisetyenziswa ngolwimi lwenkqubo. Masithi umzekelo, ulwazi esinalo kwiikhompyuter zethu luyafumaneka kwindawo yogcino lwedatha, kodwa xa kufuneka siyijonge kwaye siyilawule, isebenzisa ulwimi lwenkqubo; Kwimeko ye-MySQL, ihamba kunye ne-php, eyaziwa njengelwimi lophuhliso lwewebhu, efanayo ne-WordPress ephuhliswayo.
Sicinga ukuba singacebisa, ngokukhawuleza, ukukhuphela isixhobo seXAMPP, esifumaneka kwiinguqulelo ezahlukeneyo zeWindows. I-XAMPP iza noluhlu lwezinto, phakathi kwazo sinokuthi:
- I-Apache: Le iya kuba ngumncedisi wewebhu.
- I-PHP: Ulwimi lophuhliso lwewebhu.
- Fillezilla: Nguye ojongene nokuququzelela iifayile.
- Imercury: Yiseva yeposi, enenjongo yokwenza uvavanyo.
- I-MySQL: Njengoko besesitshilo ngaphambili, sisiseko sedatha.
Emva kokufaka i-XAMPP, uya kuba nakho ukonwabela onke la macandelo, kubandakanya i-MySQL, onokuthi uyiqale ngokuthe ngqo kwaye uqhagamshele kwi-graphical interface, yiyo loo nto i-XAMPP iluncedo kakhulu, ukongeza ekubeni unezinye izinto.
Emva kokucaca konke oku, besifuna ukucacisa ukuba phakathi kweentlobo zeetafile zokugcina idatha yethu, kwaye sithetha ngenombolo yedatha yamanani, ngaphakathi kwale nto sinazo ezinye iintlobo, kwaye kufuneka sazi ukuba yeyiphi eyona ilungileyo, eya kuthi sinike ithuba lokusebenzisa indawo yokugcina encinci kwaye iya kusinika ithuba ledatha esinethemba lokuyigcina kuloo ntsimi. Olona hlobo kuphela lokuqonda le mibuzo ziindidi ezahlukeneyo zedatha esibonelelwa yi-MySQL, apha ngezantsi siza kuba sinika olo lwazi ukuze siqonde ezona zisetyenziswayo kwiqela ngalinye.
Siyakumema ukuba ubone ikhosi ebanzi kwiindidi zedatha kwi-MySQL nayo yonke into ofuna ukuyazi ngayo, kwividiyo engezantsi ungaphoswa lithuba lokufunda!:
Idatha yamanani
Umahluko esinokuwufumana phakathi kolunye uhlobo lwedatha kunye nolunye kwi-MySQL luluhlu nje lwamaxabiso anokuqulatha. Ngaphakathi kwedatha yamanani kufuneka sibone ukuba sinako ukwahlula amasebe amabini amakhulu: iinombolo ezipheleleyo kunye nedesimali; Ngoku, singathanda ukucacisa iintlobo zeedatha zamanani esinokuthi sibe nazo ngokwemeko ethiwe thaca kuthi nento esiyifunayo:
Amanani apheleleyo
Into yokuqala esifuna ukuyichaza ngeli nqanaba kukuba ukhetho esinalo lokugcina olu hlobo lwedatha luya kuba yiminyaka, ubuninzi kunye nobukhulu ngaphandle kweziphelo. Singathanda ukubonisa umzekelo wokuqonda ngcono ukuba loluphi uhlobo lwedatha ekufuneka siyikhethile kwicandelo ngalinye:
Sinika i-TINYINT, uhlobo lwedatha esivumela ukuba sigcine elona xabiso liphezulu le-127. Ke ukuba sifuna ukuchaza intsimi kubudala babasebenzisi bethu, yile esinokuyisebenzisa, kuba uluhlu oluqhelekileyo lweminyaka lukulo nani , Kwaye ngaphandle kokuba siphila kwixesha leTestamente eNdala yebhayibhile, akukho namnye ngokwendalo owalidlula elo nani; Ke, olu hlobo lwedatha alusivumeli ukuba sigcine u-567, umzekelo, nokuba kungu-128, ukuba umda ufikelela kwi-127.
Ngoku, ukuba sifuna ukuchaza umhlaba wokuchonga imakethi enkulu ukuthengisa amawaka ezinto ezahlukeneyo nezahlukeneyo, oku kungatshintsha ngokucacileyo, ngokucacileyo i-TINYINT ayisasisebenzisi, ukongeza koku kufuneka sazi ngokuchanekileyo inani lezinto Iyathengisa, kodwa ayisiyiyo le sinayo ngoku, kodwa izama ukwenza uqikelelo ngekamva lethu elikufuphi, ngale ndlela inkqubo yethu yokugcina ayizukuphelelwa ngokukhawuleza.
Sinokusebenzisa into efana ne-SMALLINT eya kusivumela ukuba sibhale ukuya kuthi ga kumanqaku angama-32,000, kodwa ukuba sitshintsha umzekelo kwaye sisuka kwintengiso siye kwicandelo le-ID ekufuneka lisetyenziselwe itafile yabathengi yenkampani yomnxeba enabasebenzisi abazizigidi ezi-5, thina ayinakuba nayo i-SMALLINT, kodwa ezinye zinje nge-MEDIUMINT, kwaye siyaqhubeka, kwimeko apho inkampani yethu ibinabathengi abazizigidi ezingama-200, kuya kufuneka sisebenzise umhlaba wohlobo lwe-INT. Umcimbi uyatshintsha kwimeko yokufumana amandla kunye nokufuna ukuchaza intsimi echonga umntu ngamnye ohlala emhlabeni, emva koko kuya kufuneka sicele uncedo kumhlaba weBIGNIT, kuba uhlobo lwe-INT luvumela ukuya kuthi ga kumawaka amabini ezigidi iziqwenga ezahlukeneyo zedatha, kwaye ngokucacileyo ayinakufikelela kuthi.
Sifuna ukuqinisekisa ubukho bexabiso elibi, esinokuthi silifumane xa sifuna ukugcina amanqaku omdlalo, okanye uphawu olungezantsi kwe-zero itafile inokumakisha, phakathi kwezinye izinto.
Amaxabiso angatyikitywanga
Masijonge ngale ndlela: ukuba neminyaka engalunganga akunangqondo kwaphela. Ukuba kukho ukubakho kokuphindaphinda umda wexabiso elifanelekileyo ledatha nganye kususwe ukubakho kwentsimi enokugcina amaxabiso amabi, sinokuphinda kabini umda olungileyo wokugcina, kunye nomhlaba wohlobo TINYINT oqhele ukuvumela ukugcina amaxabiso Ye-127, ngoku izakuvumela ukuba ugcine amaxabiso ukusuka ku-0 ukuya ku-255.
Kwaye singawuchaza njani umhlaba ongenampawu? Ngokutshintsha okungabhaliswanga singachaza intsimi yamanani. Sisebenzisa oku kuya kufuneka sifumane ikholamu efunda iiMpawu kunye nexabiso le-UNSIGNED kwaye le ndawo ayinakuphinda ibe namaxabiso amabi, oko ke iphindaphinde amandla ayo okugcina.
Kufanelekile ukuba sikhankanye ukuba kubalulekile ukuba xa kuchazwa umhlaba kwikholamu esiya kuyifumana njengoBude sibhale inani elihambelana nomthamo wokugcina esele sikhethile. Ukuqhubeka nomzekelo wobudala, ukuba sisebenza kunye ne-TINYNIT, kufuneka sibeke ezintathu njengobude, hayi inani elikhulu okanye elincinci.
Amanani aneedesimali
Amaxabiso, imivuzo, izixa ze-akhawunti yebhanki, phakathi kwezinye izinto, siye saya kumaxabiso ngamanani kwaye siye sashiya amanani apheleleyo ngasemva, kwaye ngaphandle kwento yokuba ezi ntlobo zedatha zibizwa ngokuba "yindawo yokudada" ngenxa yokuba ikoma yahlulahlula inani elipheleleyo kunye nenxalenye yedesimali, eneneni phakathi kweentlobo zedatha ye-MySQL, iyazigcina yahlulahlula ixesha; Ukusuka apha siza kuba neentlobo ezintathu zedatha: UMKHUSELEKO, UKUQHUBEKA, kunye ne-DECIMAL.
I-FLOAT iya kusivumela ukuba sigcine ubuncinci ixabiso -999.99 kwaye ubuninzi be-999.99. Thathela ingqalelo ukuba uphawu-alubali, kodwa linqaku elibahlulayo, oko kukuthi, indawo yedesimali, ewe, yiyo loo nto benokuba ngamanani amathandathu ewonke, nangona siqaphela ukuba ezimbini zazo ziziidesimali; Kodwa sinento ebizwa ngokuba luhlu oluchanekileyo olulula, olusinyanzelayo ukuba sibe nezixa zokugqibela phakathi kwe-0 kunye ne-24.
Kwelinye icala, i-DOUBLE, iphindwe kabini ngokuchaneka, ivumela kuphela inani leendawo zokugqibela ukuba zichazwe phakathi kwama-25 nama-23. Eshiyekileyo ukuba icaciswe yi-DECIMAL, eyona ilungileyo yokugcina amaxabiso emali apho kufuneka khona ubude obungaphantsi kodwa ichaneke ngokugqibeleleyo, kwaye ngaphandle kokujikeleza, olu hlobo lwedatha lubeka ububanzi obuzinzileyo kwinani elizakuligcina. Elona nani liphezulu lolu hlobo lwedatha ngama-64, angama-30 elona nani liphezulu leendawo zokugqibela ezivunyelweyo, ngaphezulu kokwaneleyo ukugcina amaxabiso, umvuzo kunye nemali.
Idatha yeAlphanumeric
Okokugqibela sishiya udidi lwedatha yamanani ukuze singene entsha. Apha siza kuthetha ngokugcina imitya yabalinganiswa, ukuyicacisa ngendlela engcono, kwaye phakathi kweentlobo zedatha kwi-MySQL sinoku kulandelayo: CHAR, VARCHAR, BINARY, VARBINARY, TINYBLOB, TINYTEXT, BLOB, TEXT, MEDIUMBLOB, MEDIUMTEXT, I-LONGBLOB, i-LONGTEXT, i-ENUM kunye ne-SET, nganye nganye ineempawu zayo kunye neenzuzo zayo ngokuxhomekeke kwidatha esifuna ukuyigcina.
Idatha yomhla kunye nexesha
Eli iya kuba ludidi lwethu lokugqibela xa kuziwa kwiindidi zedatha kwi-MYSQL. Siza kubona ukuba sinokhetho oluninzi lokugcina idatha ekubhekiswa kuyo, imihla kunye namaxesha, ukubona umohluko phakathi kwenye kunye nezinye kunye nokusetyenziswa kwazo okuphambili, ngale ndlela siya kuba nakho ukukhetha uhlobo lwedatha efanelekileyo kwimeko nganye.
UMHLA
Olu hlobo lwedatha kwi-MySQL luyasivumela ukuba sigcine imihla apho amanani amane okuqala eyonyaka, amabini alandelayo kwinyanga kunye neyokugqibela emibini ukuya kumhla, nangona kumazwe athetha iSpanish siqhele uku-odola imihla kuqala usuku, inyanga, emva koko unyaka, kwi-MYSQL yeyona ndlela iyiyo ngokupheleleyo.
Kubalulekile ukuba wazi ukuba xa ufunda umhlaba we-DATE, nangona ubonakala ngokudibanisa ukwahlula unyaka kwinyanga kunye nenyanga ukusuka kumhla, xa ufaka le datha kusivumela ukuba senze yonke into eqhubekayo, umzekelo, siyayibona le: 2018-06-04 kwaye uyifake ngolu hlobo 20180604. Uluhlu lomhla UMHLA esivumela ukuba siwuphathe ngu-1000-01-01 ukuya ku-9999-12-31.
Ngaphandle kokuba sinento yokwenza nomsitho owenzeka kwiminyaka engamawaka amabini eyadlulayo kwaye kufuneka siwubeke elubala, asizukuba nangxaki ngale fomathi; kwelinye icala, ngenjongo yekamva sinamathuba amaninzi, kuba ngale fomathi siphantse safika kunyaka we-10,000.
IXESHA LEXESHA
Ukuba nomhlaba ochazwe njenge-DATETIME kuyakusivumela ukuba sigcine ulwazi hayi lomhla, kodwa okomzuzwana, okomzuzwana, ngaphandle komhla, kunye neshedyuli yayo, okokuqala siza kuba nonyaka, emva koko kube yinyanga, emva koko kube ngumhla , emva koko siya kuba neyure, imizuzu, kunye nemizuzwana, ifomathi ijongeka ngoluhlobo:
- YYYY- MM- DD HH: MM: SS
Inxalenye yomhla inoluhlu olufana nolo LOMHLA (10,000 yeminyaka), oko kukuthi, ukusuka ku-1000-01-01 ukuya ku-9999-12-31. Inxalenye yeshedyuli inokuhamba ngoluhlobo: ukusuka ku-00: 00: 00 ukuya ku-23: 53: 53. Yonke into egqibeleleyo inokujongeka ngoluhlobo: 1000-01-01 00:00:00 to 9999-12-31 23:59:59.
IXESHA
Apha sivunyelwe ukugcina iiyure, imizuzu kunye nemizuzwana, kwaye ewe, uhlobo lwedatha lwangaphambili lwenzile, kodwa ngeXESHA sinoluhlu oluvumelekileyo olusuka: -839: 59: 59 kuye ku-839: 59: 59; oku kungathatha malunga neentsuku ezingama-35 ukuya nokubuya kumhla wangoku. Olu hlobo lwedatha lulungele ukubala amaxesha adlulileyo phakathi kwamathuba amabini asondeleyo.
IXESHA ELITSHA
Apha sinodidi lwedatha olunokufana kakhulu kwi-DATETIME kodwa ifomathi kunye noluhlu lwahlukile, nangona isasebenza ukugcina umhla kunye nexesha. Ngentsimi yale fomathi, iindlela ezintathu zinokuziswa kuthi, eyokuqala yile: YYYY-MM-DD HH: MM: SS, owesibini ngu: YYYY-MM-DD, kwaye owesithathu ulula: YY-MM- I-DD.
Apha sinethuba lokuba nobude obunokubakho bamanani ayi-14, 8 okanye ama-6, konke kuxhomekeke kulwazi esilunikezelayo. Le fomathi ayisiyombali okanye ikamva njengeminye, kuba uluhlu olusingathwa yile ntsimi luqala kuphela ngo-1970-01-01 ukuya kunyaka ka-2037.
Ukongeza, njengenyaniso enomdla, sinokuqinisekisa ukuba ixabiso layo ligcinwa lihlaziywa ngokuzenzekelayo ngalo lonke ixesha irekhodi lifakiwe okanye lihlaziywa, ngale ndlela siya kuhlala sigcina kule ndima umhla kunye nexesha lokuhlaziywa kwethu kokugqibela kwedatha, ethi ilungile ngenene.ukuthatha ulawulo ngaphandle kwesidingo sokwenza nantoni na.
Ukuba sifuna ukuyichaza le nto kwi-phpMyAdmin, konke ekufuneka sikwenzile kukukhetha kwiimpawu ekunokukhethwa kuzo ezithi "kuhlaziyo" CURRENT_TIMESTAMP, kwaye njengexabiso elingagqibekanga CURRENT_TIMESTAMP. Indawo enexabiso elinokuhlaziywa ngokuzenzekelayo xa kufakwa okanye kuguqulwa irekhodi.
UNYAKA
Kwimeko apho kufuneka sibone isidingo sokuchaza intsimi njengoNYAKA, sinokugcina unyaka, zombini sisebenzisa ezimbini, kunye namanani amane. Kwimeko apho siyenza ngamanani amabini, ukusuka ku-70 ukuya kuma-99 (ukusukela kuma-70 ukuya kuma-99 siyakuqonda ukuba ezi ziyahambelana nonyaka ukusuka ku-1970 ukuya ku-1999, kwaye ukuba sinamanani ukusuka ku-00 ukuya ku-69 ngoko ke Ndiyaqonda ukuba ibhekisa kwiminyaka 2000 ukuya ku-2069), kwimeko enjalo yokubonelela ngamanani amane emva koko singafumanisa ukuba uluhlu olunokubakho luya kwandiswa, ukusuka ngo-1901 ukuya ku-2155.
Sinokubakho okungaphezulu, nangona kungadibaniyo neentlobo zedatha kwi-MySQL, kodwa inxulumene nemihla namaxesha. Oku kunokwenzeka ngakumbi kukuvelisa ixabiso lesitampu ngexesha lomsebenzi we-PHP (kwakhona sifuna ukucacisa ukuba asisathethi nge-MYSQL, nangona kufanelekile ukudideka ngenxa yokuba namagama afanayo).
Ngapha koko, sinokugcina elo xabiso kumhlaba we-INT oneenombolo ezili-10, ngale ndlela, kuya kuba lula kakhulu uku-odola amaxabiso endawo yethu (singabeka umhla wento yeendaba njengomzekelo) emva koko Ungawubonisa loo mhla ngokuguqula elo xesha lesitampu sexabiso sibe yinto esinokuyenza ifundeke sisebenzisa imisebenzi yokuphathwa komhla we-PHP.
Ndiyathemba ukuba ngeli nqaku malunga neentlobo zedatha kwi-MySQL, sikwazile ukwenza yonke into esifuna ukuyicacisa icace ngokwaneleyo kwaye ufunde indlela yokwenza isiseko sedatha kunye netafile ngokolwazi lwethu lonke, uchaza ngokuchanekileyo amasimi abo ukusebenzisa ezo ntlobo zedatha kunye neempawu, ke ngoko, ukuba semandleni, okanye kwiimeko, ukuqala inkqubo ngokufanelekileyo, ngoku sinombono ocacileyo wokuba yeyiphi na ifomathi esiza kuyidinga, elingana nemfuno yethu ngokoko sikuko Kufuneka wenze inkqubo.
Siyakumema ukuba ukonwabele elinye lamanqaku ethu ahambelana nenkqubo: I-Polymorphism kwinkqubo ejolise kwinto.