Omunye wemibono ebaluleke kunazo zonke kulwazi oludala ubudlelwano phakathi kwamatafula egciniwe. Lezi zinsuku zinikeza indlela yokuxhumanisa idatha egcinwe kumatafula amaningi futhi ukuyibuyisela ngendlela ephumelelayo. Ukuze udale isixhumanisi phakathi kwamatafula amabili, kufanele ucacise ukhiye wangaphandle kwelinye itafula elibhekisela kukholomu kwelinye itafula.
Amatafula weDatabases nobudlelwano
Kungenzeka usuvele wazi ukuthi imininingwane yolwazi nje yilezi zibhebhe , okufana nalokho ongase usisebenzise kakade ohlelweni lwesipredishithi , njenge-Microsoft Excel. Empeleni, ungakwazi ngisho nokuguqula ispredishithi ye-Excel ku-database. Lapho imininingwane yolwazi ihlukana khona namaspredishithi, noma kunjalo, uma kuziwa ekwakheni ubudlelwane obunamandla phakathi kwamatafula.
Cabangela, isibonelo, i-database esetshenziswa inkampani ukulandelela imininingwane yabantu. Leyo database ingaba netafula elibizwa ngokuthi Abasebenzi eliqukethe ulwazi olulandelayo ilungu ngalinye labasebenzi benkampani:
- I-ID yomsebenzi
- Igama
- Isibongo
- OfficePhone
- I-HomePhone
- I-PositionID
Kulesi sibonelo, i-ID yomsebenzi iyinani eliyingqayizivele elinikezwe isisebenzi ngasinye uma lengeziwe ku-database. I-ID yesikhundla yikhodi yomsebenzi esetshenziselwa ukukhomba isikhundla sesisebenzi enkampanini. Kulolu hlelo, isisebenzi sinomsebenzi owodwa kuphela, kodwa abasebenzi abaningi (noma cha) bangagcwalisa isikhundla ngasinye. Isibonelo, ungase ube namakhulu abasebenzi abasebenza nge-"Cashier" isikhundla.
I-database ingabuye ibe netafula okuthiwa i-Positions ngolwazi olwengeziwe olulandelayo mayelana nesimo ngasinye:
- I-PositionID
- Isihloko
- UJobeLevel
- SkillIsigaba
- Indawo
Inkambu ye-ID ye-Position kuletafula ifana nendawo ye-Employee ID etafuleni labaSebenzi - yinani elilodwa elikhiqizwayo lapho kudalwa isikhundla kwisitatimende.
Uma sihamba ukudonsa uhlu lwabasebenzi ku-database, kungokwemvelo ukucela igama lomuntu ngamunye kanye nesihloko sabo. Noma kunjalo, lolu lwazi lugcinwe kumatafula amaningi e-database, ngakho-ke lungabuyiselwa kuphela ngokusebenzisa umbuzo we-JOIN obudinga ubuhlobo obukhona phakathi kwamatafula.
Uma ubheka isakhiwo samatafula, insimu echaza ubuhlobo cishe ibonakala - inkambu ye-ID isikhundla. Isisebenzi ngasinye singaba nesimo esisodwa kuphela futhi leso sikhundla sibonakala ngokufaka i-ID ye-Position ukusuka kokungena kwetafula le-Positions. Ngaphezu kokungena ukhiye oyinhloko wethebula lezinkhundla, kulesi sibonelo, inkambu ye-ID ye-Position iyisihluthulelo sangaphandle kusuka etafuleni labaSebenzi kuya etafuleni lezinkhundla. I-database ingasebenzisa le nsimu ukuze iqondanise ulwazi kusuka kumatafula amaningi futhi iqinisekise ukuthi noma yiziphi izinguquko noma izengezo ku-database ziqhubeka nokuphoqelela ukuthembeka okubhaliwe .
Uma usuvele ukhethe ukhiye wangaphandle, ungaqhubeka futhi udonse ulwazi olufunayo kusuka ku-database usebenzisa umbuzo olandelayo:
Ukudala amakhidi angaphandle ku-SQL Server
Ngokuyisisekelo, akudingeki ukuthi uchaze ubuhlobo ngokucacile ukuthi bukwazi ukwenza imibuzo efana nale ngenhla. Kodwa-ke, uma ucacisa ngokucacile ubudlelwane usebenzisa inkinobho yangaphandle, i-database izokwazi ukwenza umsebenzi othile wokugcina indlu:
- Uma ufaka irekhodi elisha etafuleni labasebenzi, i-database izoqinisekisa ukuthi i-ID ye-Position oyifakayo iyisihluthulelo esivumelekile esiteji se-Positions.
- Uma ushintsha i-ID yokuma endaweni etafuleni lezinkhundla, i-database ingenza izibuyekezo ezidingekayo kuthebula labasebenzi ukugcina ukuvumelana.
- I-database ingakwazi ukuvikela ngokumelene nomthelela wokususwa kwesimo kusuka etafuleni lesimo ngokunquma ukususa isikhundla ngokufaka okufakiwe kwabasebenzi noma ukwenza ukususwa kwe-cascading kubo bonke abasebenzi abathintekayo.
Nakhu ukuthi ungadala kanjani ukhiye wangaphandle ku-SQL Server:
I-ALTER ITHEBHU Abasebenzi BENZA ISIQEPHU ESIKHULU (PositionID) REFERENCES Izithuba (PositionID)Ungase futhi udale ukhiye wangaphandle uma udala itafula ngokufaka lesi sigaba:
IZINTO EZIKHULULEKILEYO EZIPHUMELEKILE Izindawo (PositionID)kuze kube sekupheleni kwencazelo yekholomu yekholomu yangaphandle yesihluthulelo.