Funga nezvechimwe chinhu sechimiro
A database inowedzera simba kupfuura spreadsheet iyo yakafanana nokuti ine simba guru rekutsvaga. Relational databases cross-reference zvinyorwa mumatafura akasiyana uye kuita zviyero zvakaoma pamatare akawanda ehuwandu hwemashoko. Mashoko aya akarongeka nenzira inonyatsogadziriswa, yakawanikwa, uye inovandudzwa.
Chii Chinonzi Chiratidzo?
A database yakagadzirwa nematafura. Tafura imwe neimwe ine mapuranga nemirasi.
Mutsetse wega wega (unonzi tuple) ndeyeti data yakashandiswa kune chimwe chinhu. Chikamu chimwe nechimwe (chirevo) chinotsanangura maitiro emigwagwa. Nzvimbo yekodhidhi yepamusoro ndiyo zita rekombomira uye zviri muminda iri pasi payo mutafura mune d database.
Kana iwe uchitengesa zvigadzirwa uye ukazviisa mutafura ine mazamu eChinhuName, Pari, uye ProductID, imwe neimwe yezvinyorwa izvozvo inofunga. Mundima imwe neimwe pasi pemusoro iwoyo, iwe unopinda mazita emiti, matengo, uye maDhijiti emiti, maererano. Chimwe nechimwe chekupinda kwendima chiyeuchidzo.
Izvi zvinonzwisisika kana iwe uchifunga nezvazvo, uchipa kuti iyo isinganzwisisiki yechinangwa chekuita ndeyekuti inotsanangura unhu kana humwe hwehumwe chinhu.
Unhu Kurondedzera Makomiti
Ngatitarisei dhesi yakagadzirwa nebhizimisi. Iko inogona kunge inosanganisira matafura-anonziwo masangano nevatengi vekudhinda-Kwevashandi, Vashandi, uye Miti, pakati pevamwe. Mishonga yefurafura inotsanangura maitiro echomwe chigadzirwa.
Izvi zvinogona kusanganisira chigadzirwa chechigadzirwa, zita rezvigadzirwa, iyo ID yezvokupa (inoshandiswa sekiyi yekunze ), imwe, uye mutengo. Chimwe nechimwe chezvinhu izvi unhu hunhu hwetafura (kana sangano) inonzi Products.
Funga izvi snippet kubva munhoroondo yeNorthwinds inowanzonzi:
| ProductID | ProductName | SupplierID | CategoryID | QuantityPerU | UnitPrice |
|---|---|---|---|---|---|
| 1 | Chai | 1 | 1 | 10 mabhokisi x 20 mabhegi | 18.00 |
| 2 | Chang | 1 | 1 | 24 - 12 oz mabhodhoro | 19.00 |
| 3 | Aniseed Syrup | 1 | 2 | 12 - 550 ml mabhodhoro | 10.00 |
| 4 | Chef Anton's Cajun Mwaka | 2 | 2 | 48 - 6 oz jars | 22.00 |
| 5 | Chef Anton's Gumbo Mix | 2 | 2 | 36 mabhokisi | 21.35 |
| 6 | Ambuya va Boysenberry Vanoparadzira | 3 | 2 | 12 - 8 oz jars | 25.00 |
| 7 | Uncle Bob's Organic Akaoma Pears | 3 | 7 | 12 - 1 lb pkgs. | 30.00 |
Mazita emakoromari ndiwo maitiro echigadzirwa. Iko kunopinda muminda yemakoroni kunewo maitiro echigadzirwa.
Icho Chinoratidza Munda Wacho?
Dzimwe nguva, izwi remumunda uye chirevo zvinoshandiswa zvakasiyana, uye nokuda kwezvinangwa zvakawanda, ivo chinhu chimwe chete. Zvisinei, munda unowanzoshandiswa kurondedzera imwe sero iri patafura inowanikwa pane chero mutsara, asi chirevo chacho chinowanzoshandiswa kurondedzera chimwe chinhu chinogadziriswa muchirevo chekugadzira.
Somuenzaniso, mu tafura iri pamusoro, ProductName mumutsara wechipiri ndiChin. Iyi ndiyo munda . Kana iwe uri kukurukura nezvezvigadzirwa mumarudzi ose, ProductName ndiyo chinyorwa chechigadzirwa. Ichi ndicho chikonzero .
Usanamatira pane izvi. Kazhinji, aya mazwi maviri anoshandiswa zvakasiyana.
Kusarudzira Unhu
Zviratidzo zvinorondedzerwa maererano neshoko ravo. Chirongwa chinotsanangura zvibvumirano zvinogadziriswa izvo izvi zvingave zvine. Izvi zvinogona kusanganisira rudzi rwekutsvaga kwaro, urefu, maitiro, uye mamwe mashoko.
Semuenzaniso, chiremera chechirevo cheProduitID chinogona kutsanangura nhamba yemhando yenhamba. Chirevo chacho chinogona kuve chinotsanangurwa kuti chinoda urefu chaihwo kana kuti chingave kana chinhu chisina chinhu kana chisingazivikanwi chinotenderwa.