Qinisekisa ukuthembeka kweDatha yakho
Idibansi yolwazi, ngokulula kwayo, luhlobo lwedatha olusetyenziswa kwikholam kwi-database. Olu hlobo lwedatha lunokuba luhlobo olwakhiwe (olufana nenani okanye umtya) okanye uhlobo lwesithethe oluchaza imithintelo kwidatha.
Ukungena kweenkcukacha kunye neNdawo
Xa ufaka idatha kwifom ye-intanethi nayiphi na uhlobo-nokuba ingaba ligama lakho kunye ne-imeyile, okanye isicelo esipheleleyo somsebenzi - ifowuni igcina igalelo lakho emva kwemifanekiso. Esi saziso sivavanya ukungena kwakho ngokusekelwe kwimiqathango yemigaqo. Umzekelo, ukuba ufaka ikhowudi ye-zip, i-database ikulindele ukufumana iinombolo ezinhlanu, okanye ikhowudi ye-zip epheleleyo yase-US: iinombolo ezinhlanu zilandelwa yi-hyphen, kunye neenombolo ezine. Ukuba ufaka igama lakho kwifowuni yefowuni, i-database iya kukhononda.
Kungenxa yokuba isiseko sedatha sivavanya ukungena kwakho kwi-domain echazwe kwifowuni yefowuni. Idibansi ngokukodwa luhlobo lwedatha olunokuthi lubandakanye izithintelo zokuzikhethela.
Ukuqonda i-Domain Database
Ukuqonda isizinda seenkcukacha, makhe sicinge ngamanye ambalwa kwiinkcukacha:
- I-schema yolwazi ichaza isethi yeempawu , ezibizwa ngokuba yiikholomu okanye amasimu. Umzekelo, ukuba unetafile "Ulwazi loQhagamshelwano lwabaSebenzi," lungaquka iziganeko zeNewName, LastName, JobTitle, StreetAddress, City, State, ZipCode, PhoneNumber kunye ne-imeyile.
- Isixhobo ngasinye sinesizinda esichaza ixabiso elivumelekileyo. Oku kungabandakanya uhlobo lwedatha, ubude, ixabiso kunye nezinye iinkcukacha.
Ngokomzekelo, idibansi ye-ZipCode ye-attribute ingacacisa uhlobo lolwazi lwenombolo, njenge-integer, ngokuqhelekileyo kuthiwa yi-INT okanye i-INTEGER, kuxhomekeke kwisiseko sedatha. Okanye umqambi weenkcukacha angakhetha ukuyichaza ngokubhekiselele kunomfanekiso, ngokuqhelekileyo kuthiwa yi-CHAR. Isalathiso sinokuchazwa ngakumbi ukuba sidinga ubude obuthile, nokuba ngaba ixabiso elingenanto okanye elingaziwa livumelekile.
Xa ubutha ndawonye zonke izinto ezichaza isizinda, ugqiba ngolunye uhlobo lweedatha olukhethiweyo, oluthiwa "uhlobo oluthile lwedatha" okanye iDT.
Ngokungqinelana neDesi
Imilinganiselo evunyelweyo yembambano yokudala idibansi , eqinisekisa ukuba yonke idatha ensimini iqulethe ixabiso elifanelekileyo.
Ubungqina bendawo buchazwe ngu:
- Uhlobo lweedatha, njenge-integer, umgca okanye i-decimal
- Ubude obuvumelekileyo beenkcukacha
- Uluhlu, ukuchaza imida ephezulu nangaphantsi
- Nayiphi na imithintelo , okanye imida kwiimpawu ezivumelekileyo. Umzekelo, ifowuni ye-zip code ye-US inokunyanzelisa ikhowudi epheleleyo ye-ZIP + 4 , okanye ikhowudi eneenombolo ezilisithoba.
- Uhlobo lwenkxaso ye-NULL, okanye ingaba isimboli sinokungaziwa, okanye ixabiso le-NULL
- Inani elingagqibekanga, ukuba kukho
- Ifomathi yomhla, xa kusebenza (umzekelo, dd / mm / yy okanye mm / dd / yyyy)
Ukudala i-Domain
Iingxelo zolwazi ezisebenzisa i- SQL (uLwimi oluCwangcisiweyo lweSicelo) okanye i-flavour ye-SQL, sebenzisa umyalelo we CREATE DOMAIN SQL.
Ngokomzekelo, isitatimende sokwenzayo apha sikwenza umxholo weZipCode wolwazi lwe-CHAR kunye nabalingani abahlanu. I-NULL, okanye inani elingaziwa, alivumelekanga. Uluhlu lweedatha lumele lube phakathi kwe "00000" kunye ne "99999." ludala umxholo weZipCode wolwazi lwe-CHAR kunye nabalingani abahlanu. I-NULL, okanye inani elingaziwa, alivumelekanga. Uludwe lweedatha kufuneka luwele phakathi kwe "00000" kunye ne "99999."
DALA DOMAIN ZipCode I-CHAR (5) AKUKHO I-NULL CHECK (VALUE> '00000' NOKUBALULEKA
Yonke inhlobo yedatha inikeza indlela yokuchaza isethi yemingcele kunye nemithetho elawula idatha engavumelekanga, nangona ingabibi i-domain. Khangela amaxwebhu akho eenkcukacha zeenkcukacha.