Iziphambeko Ezivamile Ezenziwe Ngomdwebo WeDathayli

Kungakhathaliseki ukuthi usebenza ne-database enamakhulu amarekhodi noma izigidi zamarekhodi, ukuklanywa kwe-database efanele kuhlale kubalulekile. Ngeke nje kube lula ukuthola imininingwane kalula, kuzokwenza kube lula nokwandisa imininingwane esikhathini esizayo. Ngeshwa, kulula ukuwela ezingcupheni ezimbalwa ezingenza izinto zibe nzima esikhathini esizayo.

Kunezincwadi zonke ezibhalwe ngokuphathelene nokujwayelekile kwe-database, kodwa uma ugcina nje lezi ziphutha ezivamile, uzobe usendleleni efanele ekuklanyelwe kahle kwedatha.

I-Database Mistake # 1: Ukuphindaphinda Amasimu Etafuleni

Isimiso esiyisisekelo sesithupha somklamo omuhle we-database ukukhumbula idatha yokuphinda nokubeka lawo kholomu ephinda etafuleni labo. Ukuphinda amasimu etafuleni kuvamile kulabo abavela ezweni lama-spreadsheet, kepha ngenkathi amaspredishithi ejwayele ukuba flat nge design, yolwazi kufanele kube relational. Kufana nokuhamba kusuka ku-2D kuya ku-3D.

Ngenhlanhla, amasimu okuphindaphinda ngokuvamile kulula ukuwabona. Vele ubuke kuleli tafula:

Kwenzekani uma umyalelo uqukethe imikhiqizo emine? Sidinga ukwengeza enye insimu etafuleni ukusekela imikhiqizo engaphezu kweyodwa. Futhi uma sakhele uhlelo lokusebenza lwekhasimende elizungeze itafula ukuze lisisize idatha yokufaka, singadinga ukuyiguqula ngensimu entsha yomkhiqizo. Futhi sithola kanjani yonke imiyalo nge-Jellybeans ku-oda? Sizophoqeleka ukucubungula yonke insimu yomkhiqizo etafuleni ngesitatimende se-SQL esingase sibonakale: KUKHOLEKA * KUSUKA Imikhiqizo KUNYE UMkhiqizo1 = 'I-Jelly Beans' OR Product2 = 'Jelly Beans' OR Product3 = 'Jelly Beans'.

Esikhundleni sokuba netafula elilodwa elifaka yonke imininingwane ndawonye, ​​kufanele sibe namatafula amathathu ngamunye abambe ucezu oluthile lolwazi. Kulesi sibonelo, singathanda itafula le-oda ngolwazi mayelana ne-oda ngokwalo, ithebula lemikhiqizo nayo yonke imikhiqizo yethu kanye nethebhulethi ye-ProductOrders ehlanganiswe imikhiqizo ngomyalelo.

Qaphela ukuthi ithebula ngalinye linamakhethi akhe ahlukile e-ID. Lona ukhiye oyinhloko. Sixhumanisa amathebula ngokusebenzisa i-key key value njengesihluthulelo sangaphandle kwelinye itafula. Funda kabanzi mayelana nezihluthulelo eziyisisekelo nezikhiphe zangaphandle.

I-Database Mistake # 2: Ukushumeka Ithebula Kuthebula

Lokhu kungenye iphutha elivamile, kodwa akuhlali njalo ngokuma okuningi njengamasimu aphindaphindiwe. Uma uhlela i-database, ufuna ukuqinisekisa ukuthi yonke idatha etafuleni ihlobana nayo. Kufana nomdlalo womntwana mayelana nokubona okuhlukile. Uma unamabhanana, i-strawberry, i-peach kanye nesethi yethelevishini, ithelevishini ishiwo cishe kwenye indawo.

Ngaphakathi kwemigqa efanayo, uma unetafula labantu abathengisayo, lonke ulwazi kulesi sithebula kufanele lubhekane ngqo nalowo muntu wokuthengisa. Noma yiluphi ulwazi oluthe xaxa olungafani nalo muntu wokuthengisa lungase lube kwenye indawo ku-database yakho.

Ngenkathi leli tafula lingase libukeke sengathi lihlobene nomthengisi ngamunye, empeleni kunethebula elihlanganisiwe ngaphakathi kwetafula. Phawula ukuthi iHhovisi ne-OfficeNumber iphinda kanjani "ne-Austin Downtown". Kuthiwani uma inombolo yefoni ehhovisi ishintsha? Kuzodingeka ubuyekeze yonke isethi yedatha ngolwazi olulodwa olulodwa lokuguqula ulwazi, okungeyona into enhle. Lezi zinsimu kufanele zihanjiswe etafuleni labo.

Lolu hlobo lokuklama lunikeza ikhono lokungeza ulwazi oluthe xaxa etafuleni leHhovisi ngaphandle kokudala ubusuku obunzima betafula etafuleni lomthengisi. Cabanga ukuthi bekuyoba umsebenzi omkhulu kangakanani ukugcina ithrekhi yekheli lesitaladi, idolobha, izwe kanye nekhodi ye-zip uma yonke leyo mininingwane yayisetafuleni lomuntu wokuthengisa!

I-Database Mistake # 3: Ukubeka Izingxenye ezimbili noma eziningi Ukwaziswa Ensimini Yodwa

Ukushumeka kolwazi lwehhovisi ngaphakathi kwetafula lomthengisi kwakungeyona yinkinga kuphela yale database. Insimu yekheli iqukethe izingcezu ezintathu zolwazi: ikheli lomgwaqo, idolobha kanye nezwe. Insimu ngayinye ku-database kufanele iqukathe ucezu olulodwa lwolwazi. Uma unezingcezu eziningi zolwazi ensimini eyodwa, kungaba nzima ukubuza imininingwane yolwazi.

Isibonelo, kuthiwani uma sifuna ukuqhuba umbuzo kubo bonke abathengisi base-Austin? Sidinga ukucinga ngaphakathi kwenkambu yekheli, okungesiyo kuphela ephumelelayo, kodwa ingabuyisa ulwazi olubi. Ngemuva kwalokho, kwenzekani uma othile ehlala e-Austin emgwaqweni ePortland, e-Oregon?

Nakhu ukuthi ithebula kufanele libukeke kanjani:

Kukhona izinto ezimbalwa okufanele wazi lapha. Okokuqala, "Ikheli" ne "Ikheli2" lizobonakala liwela ngaphansi kwemikhawulo ephindaphindiwe.

Kodwa-ke, kulokhu babhekisela ezingxenyeni ezihlukene zedatha ezihlobene ngqo nomuntu wokuthengisa kunokuba iqembu eliphindaphinda lemininingwane okufanele lihambe etafuleni layo.

Futhi, njengephutha lebhonasi ukugwema, phawula ukuthi ukufometha kwenombolo yocingo kukhishwe kanjani etafuleni. Kufanele ugweme ukugcina ifomethi yamasimu lapho kungenzeka. Endabeni yezinombolo zocingo, kunezindlela eziningi abantu abhala inombolo yocingo: 215-555-5858 noma (215) 555-5858. Lokhu kuzokwenza ukufuna umuntu wokuthengisa ngenombolo yabo yocingo noma ukwenza usesho lwabantu abathengisa ikhodi yendawo efanayo kunzima kakhulu.

I-Database Mistake # 4: Akusebenzi Ukusebenzisa Ukhiye Oyinhloko

Ezimweni eziningi, uzofuna ukusebenzisa inombolo ekhulayo ngokuzenzakalelayo noma enye inombolo eyenziwe noma i-alphanumeric ukhiye wakho oyinhloko. Kufanele ugweme ukusebenzisa noma yiluphi ulwazi lwangempela ukhiye oyinhloko ngisho noma kubonakala sengathi kungenza isihlonzi esihle.

Isibonelo, ngamunye wethu unenombolo yakhe yokuphepha yomuntu siqu, ngakho-ke ukusebenzisa inombolo yokuphepha yomphakathi kubasebenzi bezinsiza kungase kuzwakale njengomqondo omuhle. Kodwa nakuba kungavamile, kungenzeka ngisho nenombolo yokuphepha yomphakathi ukushintsha, futhi asifuni neze ukhiye wethu oyinhloko ukushintsha.

Futhi leyo yinkinga ngokusebenzisa ulwazi langempela njengenani elibalulekile. Lingashintsha.

I-Database Mistake # 5: Ayisebenzisi Isivumelwano Sokuqamba Amagama

Lokhu kungase kungabonakali njengento enkulu lapho uqala ukuklama imininingwane yakho, kodwa uma ufika endaweni yokubhala imibuzo ngokumelene nedatha ukuze uthole ulwazi, ukuba nomhlangano wokuqamba igama kuzokusiza njengoba ukhumbuza amagama ensimu ngekhanda.

Cabanga nje ukuthi kunzima kangakanani leyo nqubo ukuthi ngabe ngabe amagama agcinwe njenge-FirstName, LastName etafuleni elilodwa kanye ne-first_name, last_name kwelinye itafula.

Imihlangano emibili edumile kakhulu yokuqamba amagama ibeka phambili incwadi yokuqala yegama ngalinye ensimini noma ukuhlukanisa amagama usebenzisa i-underscore. Ungase ubone abathuthukisi abathile befaka igama leyokuqala lalo lonke igama ngaphandle kwegama lokuqala: firstName, lastName.

Uzophinde uthande ukunquma ukusebenzisa amagama amathebula angamanye noma amagama etafula lamaningana. Ingabe itafula le-oda noma ithebula le-oda? Ingabe itafula leKhasimende noma ithebula lamakhasimende? Futhi, awufuni ukunamathela kuthebula le-oda kanye netafula lamakhasimende.

Umhlangano wokuqamba igama owukhethayo awubalulekile njengenqubo yokukhetha ngempela nokunamathela emhlanganweni wokuqamba igama.

I-Database Mistake # 6: Ukuhlaziya okungalungile

Ukukhomba ngokukodwa kungenye yezinto ezinzima kunazo zonke ukuze uthole ilungelo, ikakhulukazi kulabo abasha ku-design design. Zonke izihluthulelo eziyinhloko nezikhiwane zangaphandle kufanele zibekwe indexed. Lezi yiziphi izibhebhe zokuxhumanisa ndawonye, ​​ngakho-ke ngaphandle kwenkomba, uzobona ukusebenza okubi kakhulu ngaphandle kwedatha yakho.

Kodwa yiziphi ezinye izinto ezingabanjwanga kakhulu. Lezi yizinkambu ze "WHERE". Uma uvame ukunciphisa ukusesha kwakho ngokusebenzisa insimu ku-WHERE clause, ufuna ukucabanga ngokubeka inkomba kuleyo nsimu. Kodwa-ke, awufuni ukubhala ngokweqile ithebula, elingalimaza ukusebenza.

Unganquma kanjani? Lokhu kuyingxenye yobuciko bokuklanywa kwedatha. Ayikho imingcele elukhuni ukuthi zingaki izinkomba okufanele uzibeke phezu kwetafula. Ngokuyinhloko, ufuna ukukhomba noma iyiphi insimu evame ukusetshenziswa esinqunqutheleni esiphila khona. Funda kabanzi mayelana nokukhomba kahle i-database yakho.