Ngabe ufunda ngabaphathi be-database? Uma kunjalo, udinga ukuzazisa nge izinhlobo zedatha ku-MySQL, enye yezinto ezinhle kakhulu futhi ezisetshenziswa kakhulu emhlabeni. Ungaphuthelwa ithuba!.
Izinhlobo zedatha ku-MySQL
Ngaso sonke isikhathi lapho sidinga ukudala itafula elingasetshenziswa ukugcina idatha yohlelo lokusebenza, kufanele sazi ukuthi singabona kanjani ukuthi yiluphi uhlobo lwedatha olusisiza ukugcina kangcono konke esikudingayo ukuze sikugcine. Singakhetha phakathi kokuthathu: idatha yezinombolo, izintambo (i-alphanumeric), nezinsuku nezikhathi.
Kulezi zinkambu zamatafula e-MYSQL sinethuba lokukhetha phakathi kwezinhlobo ezintathu zokuqukethwe, futhi yize kubonakala kusobala, thola ukuthi idatha yethu sizoyithumela kuphi, isitoreji esizoba yiluphi iqembu, lapha sinesibonelo sokuzibeka kumongo: yebo sidinga inkambu esingagcina ngayo iminyaka yomuntu, khona-ke kungaba yinkambu yedatha yezinombolo.
Kepha ngaphambi kokuthi ngiqhubeke nokuchaza, uyazi ukuthi yini i-MySQL? Kuyaziwa njengomunye wabaphathi bemininingwane evulekile esetshenziswa kakhulu emhlabeni. Ukuze sibe nombono wokuthi ithandwa kanjani, sizokutshela ukuthi: I-WordPress ingumphathi wezinhlobo ezahlukahlukene zokuqukethwe, okukhona kusukela ngo-2003, nokuthi cishe ama-55% kuya kuma-60% wamakhasi e-web exist, yenziwe ngenxa yalokhu, futhi isebenzisa i-MySQL njenge-database, ngakho-ke lokhu kufakazela ukuthi ingaba lusizo kangakanani nobubanzi enabo.
I-MySQL ingeyenkampani yakwa-Oracle Corporation, eyayiphethe ukuyithenga ngo-2010. Le menenja inokusetshenziswa okuningi, okufana: nokwenza, ukufaka ukufaka, ukulungisa amakhasi e-web, ukufunda idatha, phakathi kokunye.
Lo mshayeli angalandwa kalula futhi unezinguqulo eziningana ngokuya ngeWindows oyisebenzisayo, ngendlela efanayo, kulula kakhulu ukuyifaka.
Iningi labaphathi be-database lisetshenziswa ngolimi lohlelo. Masithi ngokwesibonelo, imininingwane esinayo kumakhompyutha ethu iyatholakala ku-database, kepha lapho sidinga ukuyibona ngeso lengqondo futhi siyiphathe, isebenzisa ulimi lokuhlela; Endabeni ye-MySQL, ihambisana ne-php, eyaziwa njengelimi lokuthuthukisa iwebhu, okufanayo ne-WordPress eyakhiwa.
Sicabanga ukuthi singancoma, ngejubane, ukulanda ithuluzi le-XAMPP, elitholakala ngezinhlobo ezahlukahlukene zeWindows. I-XAMPP iza nochungechunge lwezinto, phakathi kwazo esinazo:
- I-Apache: Lokhu kungaba iseva yewebhu.
- I-PHP: Ulimi lokuthuthukiswa kwewebhu.
- Fillezilla: Nguye ophethe ukuhlanganisa amafayela.
- IMercury: Yiseva yeposi, enenhloso yokwenza izivivinyo.
- I-MySQL: Njengoba sishilo ekuqaleni, yiseva yedatha.
Ngemuva kokufaka i-XAMPP, uzokwazi ukujabulela zonke lezi zinto, kufaka phakathi i-MySQL, ongayiqala ngqo bese uxhuma kusixhumi esibonakalayo, yingakho i-XAMPP ilusizo olukhulu, ngaphezu kokuba nezinye izingxenye.
Njengoba konke lokhu kucacile, besifuna ukuchaza ukuthi phakathi kwezinketho zethu zezinhlobo zamatafula zokugcina idatha yethu, futhi sikhuluma ngenkambu yedatha yamanani, ngaphakathi kwalokhu sinezinye izinhlobo, futhi kufanele sazi ukuthi yikuphi okungcono kakhulu, okunganikeza thina ithuba lokudla isikhala esincane sokugcina futhi sizosinika ithuba ledatha esinethemba lokuyigcina kulowo mkhakha. Ukuphela kwendlela yokuqonda le mibuzo yizinhlobo ezahlukahlukene zedatha i-MySQL esinikeza yona, ngezansi sizobe sihlinzeka lolo lwazi ukuze siqonde ukusetshenziswa okufanele kweqembu ngalinye.
Sikumema ukuba ubone inkambo ejulile yezinhlobo zedatha ku-MySQL nakho konke odinga ukukwazi ngakho, kuvidiyo engezansi. Ungaphuthelwa yithuba lokufunda!:
Idatha yenombolo
Umehluko esingawuthola phakathi kohlobo oluthile lwedatha nolunye ku-MySQL kumane nje kungukuhla kwamanani angawaqukatha. Ngaphakathi kwedatha yezinombolo sidinga ukubona ukuthi singahlukanisa amagatsha amabili amakhulu: izinombolo kanye namadesimali; Manje, sithanda ukuchaza izinhlobo zemininingwane yezinombolo esingaba nayo ngokwesimo esethulwe sona nalokho esikudingayo:
Izinombolo zamanani
Into yokuqala esifuna ukuyichaza kuleli qophelo ukuthi izinketho esinazo zokugcina lolu hlobo lwedatha kungaba yiminyaka, ubuningi nobukhulu ngaphandle kwamanani. Sithanda futhi ukwethula isibonelo ukuze siqonde kangcono ukuthi hlobo luni lwedatha okufanele siyikhethe ngenkambu ngayinye:
Sethula i-TINYINT, uhlobo lwedatha esivumela ukuthi sigcine inani eliphakeme elingu-127. Ngakho-ke uma sidinga ukuchaza inkambu yeminyaka yabasebenzisi bethu, lena yiyona esingayisebenzisa, ngoba ibanga leminyaka elijwayelekile liphakathi kwaleyo nombolo , futhi ngaphandle kokuthi siphila esikhathini seTestamente Elidala eliseBhayibhelini, akekho noyedwa owadlula lelo nani ngokwemvelo; Ngakho-ke cha, lolu hlobo lwedatha alusivumeli ukuthi sigcine u-567, ngokwesibonelo, hhayi ngisho no-128, uma umkhawulo ufinyelela ku-127.
Manje, uma sifuna ukuchaza inkambu yokukhomba imakethe enkulu ukuthengisa izinkulungwane zezinto ezahlukahlukene nezihlukahlukene, lokhu kuzoshintsha kakhulu, ngokusobala i-TINYINT ayisasisebenzisi, ngaphezu kwalokhu kufanele sazi ngokunembile inani lezinto liyathengisa, kodwa hhayi ngalokhu esinakho njengamanje, kodwa sizama ukubikezela ngekusasa lethu eliseduze, ngale ndlela uhlelo lwethu lokugcina ngeke lusheshe luphelelwe yisikhathi.
Singasebenzisa into efana ne-SMALLINT ezosivumela ukuthi sifinyelele kuma-athikili angama-32,000, kepha uma siguqula isibonelo bese sisuka emakethe siye enkambini ye-ID okufanele isetshenziselwe itafula lamakhasimende lenkampani yezingcingo enabasebenzisi abayizigidi ezi-5, thina besingasenayo i-SMALLINT, kepha ngokunye okufana ne-MEDIUMINT, futhi siyaqhubeka, esimweni lapho inkampani yethu ibinamakhasimende ayizigidi ezingama-200, kufanele sisebenzise inkambu yohlobo lwe-INT. Inkinga iyashintsha esimweni sokungabi namqondo futhi sifune ukuchaza inkambu ekhomba umuntu ngamunye ohlala emhlabeni oyiplanethi, lapho-ke kufanele sicele insimu ye-BIGNIT usizo, ngoba uhlobo lwe-INT luvumela kuphela izigidi eziyizinkulungwane ezimbili izingcezu ezahlukahlukene zedatha, futhi lokho ngokusobala bekungeke kusifinyelele.
Sifuna futhi nokuqinisekisa ubukhona bamanani amabi, esingawathola lapho sifuna ukugcina amaphuzu womdlalo, noma umaki ongezansi kukaziro ongamakwa yithebula, phakathi kwezinye izinto.
Amanani angasayiniwe
Ake sikubheke ngale ndlela: ukuba neminyaka engemihle akunangqondo nakancane. Uma kunethuba lokuphinda kabili umkhawulo wenani eliphakeme kakhulu ledatha ngayinye kususwe ukuthi leyo nkambu ingagcina amanani amabi, sizobe siphinda kabili umkhawulo omuhle wesitoreji, nenkambu yohlobo TINYINT evame ukuvumela ukugcina amanani Ka-127, manje kuzokuvumela ukuthi ugcine amanani kusuka ku-0 kuye ku-255.
Futhi siyichaza kanjani inkambu engenasibonakaliso? Ngokuguqula okungasayiniwe singachaza inkambu yezinombolo. Sisebenzisa lokhu kufanele sithole ikholomu efunda Izimfanelo nenani le-UNSIGNED futhi le nkambu ayisakwazi ukuba namanani amabi, ngaleyo ndlela iphindwe kabili amandla ayo okugcina.
Kubalulekile ukuthi sisho ukuthi kubalulekile ukuthi lapho kuchazwa inkambu kukholamu esizoyithola njenge-Length sibhale inombolo ehambisana nomthamo wesitoreji esisanda kuwukhetha. Ukuqhubeka nesibonelo seminyaka, uma sisebenza ne-TINYNIT, kufanele sibeke abathathu njengobude, hhayi inombolo enkulu noma encane.
Izinombolo ezinamadesimali
Amanani, amaholo, amanani we-akhawunti yasebhange, phakathi kokunye, sidlulisele kumanani ezinombolo anama-decimals futhi sishiye ngemuva izinombolo, futhi ngaphandle kokuthi lezi zinhlobo zedatha zibizwa ngokuthi "indawo entantayo" ngoba ukhefana uhlukanisa ingxenye ephelele ingxenye yedesimali, empeleni phakathi kwezinhlobo zedatha ye-MySQL, iwagcina ebahlukanisa nesikhathi; kusuka lapha sizoba nezinhlobo ezintathu zedatha: I-FLOAT, DOUBLE ne-DECIMAL.
I-FLOAT izosivumela ukuthi sigcine okungenani inani -999.99 futhi okungenani libe ngu-999.99. Cabanga ukuthi isibonakaliso - asibali, kepha iphuzu elibahlukanisayo, okungukuthi, iphoyinti ledesimali, yebo, yingakho kungaba ngamadijithi ayisithupha esewonke, noma kunjalo siqaphela ukuthi amabili awo angamadesimali; Kepha sinokuthile okubizwa ngokuthi ibanga elilula lokunemba, okusiphoqa ukuthi sibe nenani ledesimali eliphakathi kuka-0 no-24.
Ngakolunye uhlangothi, i-DOUBLE, ukuphindwa kabili kokunemba, kuvumela kuphela inani lezindawo zamadesimali ukuthi zichazwe phakathi kuka-25 no-23. Ukusebenzisa i-FLOAT, okucacile okulula, kungadala izinkinga zokujikeleza nokulahleka kwezindawo ezisele zamadesimali. Okusele ukuthi kuchazwe yi-DECIMAL, okungcono kakhulu ukugcina amanani emali lapho kudingeka khona ubude obuncane kepha ukunemba okuphezulu, futhi ngaphandle kokuzungeza, lolu hlobo lwedatha lunikeza ububanzi obulungisiwe enombolweni ezogcinwa. Inani eliphelele lamadijithi alolu hlobo lwedatha angama-64, okuyi-30 yawo okuyisibalo esiphezulu sezindawo zamadesimali ezivunyelwe, ngaphezu kokwanele ukugcina amanani, amaholo nezimali.
Idatha ye-Alphanumeric
Ekugcineni sishiya isigaba semininingwane yezinombolo ukuze sifake entsha. Lapha sizobe sikhuluma ngokugcina izintambo zezinhlamvu, ukuzichaza ngendlela engcono, futhi phakathi kwezinhlobo zedatha ku-MySQL sinakho okulandelayo: CHAR, VARCHAR, BINARY, VARBINARY, TINYBLOB, TINYTEXT, BLOB, TEXT, MEDIUMBLOB, MEDIUMTEXT, I-LONGBLOB, LONGTEXT, ENUM ne-SET, ngayinye inezici zayo nezinzuzo zayo ngokuya ngokuthi iyiphi idatha esifuna ukuyigcina.
Idatha nesikhathi nesikhathi
Lesi kungaba isigaba sethu sokugcina uma kukhulunywa ngezinhlobo zedatha ku-MYSQL. Sizobona ukuthi sinezinketho eziningana zokugcina idatha ebhekisiwe, izinsuku nezikhathi, ukubona umehluko phakathi kokunye nokusetshenziswa kwazo okuyinhloko, ngale ndlela sizokwazi ukukhetha uhlobo olufanele lwedatha esimweni ngasinye.
DATE
Lolu hlobo lwedatha ku-MySQL lusivumela ukuthi sigcine izinsuku lapho amadijithi amane okuqala azoba ngawonyaka, amabili alandelayo aye enyangeni futhi amabili okugcina osukwini, yize emazweni akhuluma iSpanishi sijwayele uku-oda izinsuku kuqala ngosuku, bese kuba yinyanga, bese kuba unyaka, kwe-MYSQL kungenye indlela ezungeze ngokuphelele.
Kubalulekile ukwazi ukuthi lapho ufunda inkambu ye-DATE, yize ivela ngamadeshi ahlukanisa unyaka nenyanga nenyanga kusukela osukwini, lapho kufakwa le datha kusivumela ukuthi senze konke okuqhubekayo, ngokwesibonelo, singakubona njenge lokhu: 2018-06-04 bese uyifaka kanjena 20180604. Ibanga ledethi i-DATE esivumela ukuthi siliphathe ngu-1000-01-01 kuya ku-9999-12-31.
Ngaphandle kokuthi sibe nokuthintana nomcimbi owenzeka eminyakeni eyizinkulungwane ezimbili edlule futhi sidinga ukuwudalula, ngeke sibe nezinkinga ngale ndlela; ngakolunye uhlangothi, uma sibheka esikhathini esizayo sinamathuba amaningi, ngoba ngale fomethi sifinyelela cishe unyaka we-10,000.
ISIKHATHI SESIKHATHI
Ukuba nenkambu echazwe njengo-DATETIME kuzosivumela ukuthi sigcine imininingwane hhayi yosuku, kepha yesikhashana, isikhathi esisheshayo, ngaphandle kwedethi, nohlelo lwayo, okokuqala sizoba nonyaka, bese kuba yinyanga, bese kuba usuku , lapho-ke futhi sizoba nehora, imizuzu, kanye nemizuzwana, ifomethi ibukeka kanjena:
- YYYY- MM- DD HH: MM: SS
Ingxenye yedethi inobubanzi obufana nobohlobo lwe-DATE (iminyaka eyi-10,000), okusho ukuthi, kusuka ku-1000-01-01 kuye ku-9999-12-31. Ingxenye yeshejuli izohamba kanjena: kusuka ku-00: 00: 00 kuye ku-23: 53: 53. Konke okuphelele kungabukeka kanjena: 1000-01-01 00:00:00 to 9999-12-31 23:59:59.
ISIKHATHI
Lapha sivunyelwe ukugcina amahora, imizuzu namasekhondi, futhi yebo, uhlobo lwangaphambilini lwedatha nalo luye lwenza kanjalo, kodwa nge-TIME sinebanga elivunyelwe elisuka ku: -839: 59: 59 kuye ku-839: 59: 59; lokhu kuzoba cishe izinsuku ezingama-35 emuva naphambili ngosuku lwamanje. Lolu hlobo lwedatha lulungele ukubala izikhathi ezidlulile phakathi kwezikhathi ezimbili eziseduze.
ISIKHATHI SESIKHATHI
Lapha sinohlobo lwedatha olungafana kakhulu ne-DATETIME kepha ifomethi nobubanzi bayo buhlukile, yize kusasebenziseka ekugcineni usuku nesikhathi. Ngenkambu yale fomethi, izinketho ezintathu zingavezwa kithi, eyokuqala yile: YYYY-MM-DD HH: MM: SS, eyesibili ithi: YYYY-MM-DD, kanti eyesithathu ilula: YY-MM- DD.
Lapha sinethuba lokuba nobude obungahle bube ngamadijithi ayi-14, 8 noma ama-6, konke kuya ngolwazi esilunikezayo. Le fomethi ayifani nomlando noma ikusasa njengamanye, ngoba ibanga elisingathwa yile nkambu lisuka kuphela ngo-1970-01-01 kuya onyakeni ka-2037.
Ngaphezu kwalokho, njengeqiniso elinqatshelwayo, singathola ukuthi inani lalo ligcinwa livuselelwa ngokuzenzakalela ngaso sonke isikhathi lapho irekhodi lifakwa noma livuselelwa, ngale ndlela sizohlala sigcina kulo mkhakha usuku nesikhathi sokubuyekezwa kwethu kokugcina kwaleyo datha, okuyinto ilungele ngempela.ukulawula ngaphandle kokuhlela noma yini.
Uma sifuna ukukuchaza lokhu kusuka ku-phpMyAdmin, konke okumele sikwenze ukukhetha ku-Attributes inketho ethi "on update" CURRENT_TIMESTAMP, futhi njengenani elizenzakalelayo CURRENT_TIMESTAMP. Inkambu inani lalo elingabuyekezwa ngokuzenzakalela lapho kufakwa noma kuguqulwa irekhodi.
UNYAKA
Uma kwenzeka sidinga ukuchaza inkambu njengo-YEAR, singagcina unyaka, sisebenzisa amadijithi amabili namane. Uma kwenzeka ukuthi sikwenze ngamadijithi amabili, kusuka ku-70 kuye ku-99 (kusuka ku-70 kuye ku-99 sizoqonda ukuthi lezi zihambelana nobubanzi beminyaka kusuka ku-1970 kuya ku-1999, futhi uma sinamadijithi asuka ku-00 kuye ku-69 lapho-ke ukuqonda ukuthi kubhekisa eminyakeni 2000 kuya ku-2069), esimweni esinjalo sokuhlinzeka ngamadijithi amane lapho-ke sizothola ukuthi ububanzi obungenzeka buzonwetshwa, bese kusuka ku-1901 kuye ku-2155.
Futhi sinethuba elengeziwe, yize lingahlobene nezinhlobo zedatha ku-MySQL, kepha lihlobene nezinsuku nezikhathi. Lokhu kungenzeka okungeziwe ukukhiqiza inani lesitembu sesikhathi ngomsebenzi wesikhathi se-PHP (futhi sifuna ukucacisa ukuthi asisakhulumi nge-MYSQL, yize kuvumelekile ukudideka ngenxa yokuba namagama afanayo).
Noma kunjalo, singaligcina lelo nani emkhakheni we-INT onamadijithi ayi-10, ngale ndlela, kuzoba lula kakhulu uku-oda amanani wensimu yethu (singabeka usuku lwendaba njengesibonelo) bese thina ingakhombisa lolo suku ngokuguqula leso sitembu sesikhathi sibe yinto esingayenza ifundeke sisebenzisa imisebenzi yokuphatha usuku lwe-PHP uqobo.
Ngiyethemba ukuthi ngale ndatshana yezinhlobo zedatha ku-MySQL, sikwazile ukwenza konke ebesifuna ukukuchaza kucace ngokwanele nokuthi ufunde ukuthi ungakha kanjani i-database kanye netafula ngokuvumelana nayo yonke imininingwane yethu, sichaze ngokunemba okuphelele izinkambu zabo sisebenzisa izinhlobo zedatha nezimpawu, ngakho-ke, ukuba semandleni, noma ezimweni, ukuqala ukuhlela kahle, manje sinombono ocacile wokuthi iyiphi ifomethi esizoyidinga, elingana isidingo sethu ngokuya ngalokho esikudingayo kufanele ngihlele.
Sikumema ukuthi uthokozele enye yezindatshana zethu ezihlobene nohlelo: I-Polymorphism ezinhlelweni ezigxile entweni.