Malamulo awiri osavutawa angakuthandizeni kuti muzisunga malamulo anu
Fomu Yoyamba Yoyamba (1NF) imakhazikitsa malamulo oyambirira a malo osungirako zinthu:
- Chotsani mazenera ophatikiza kuchokera pa tebulo lomwelo.
- Pangani matebulo osiyana pa gulu lirilonse la chidziwitso ndi kuzindikira mzere uliwonse ndi mzere wapadera (key key).
Kodi malamulowa amatanthauzanji pamene mukuganiziranso zadongosolo lachinsinsi? Ndizosavuta kwenikweni.
1. Kuthetsa Kuwerengera
Lamulo loyambirira limapereka kuti sitiyenera kupindula deta mkati mwa mzere umodzi wa tebulo. M'mudzi wa deta, malingaliro ameneĊµa akutchulidwa ngati atomu la tebulo. Ma tebulo omwe amatsatira lamuloli amanenedwa kukhala atomiki. Tiyeni tifufuze mfundo iyi ndi chitsanzo chotsatira: tebulo mkati mwachinsinsi cha anthu omwe amasungira ubale wawo. Pa cholinga cha chitsanzo chathu, tidzakhazikitsa lamulo la bizinesi kuti mtsogoleri aliyense akhoza kukhala ndi mmodzi kapena angapo omwe ali pansi pake pamene aliyense ali ndi mtsogoleri mmodzi yekha.
Intuitively, pakupanga mndandandanda kapena spreadsheet kuti muwerenge nkhaniyi, tikhoza kupanga tebulo ndi zotsatirazi:
- Mtsogoleri
- Mtsogoleri1
- Otsatira2
- Pansi3
- Pansi4
Komabe, kumbukirani lamulo loyamba loperekedwa ndi 1NF: Chotsani mapepala ophatikiza kuchokera pa tebulo lomwelo. Mwachiwonekere, zigawo za Sub-1-Subordinate4 ndizophatikiza. Tengani kamphindi ndikusinkhasinkha mavuto omwe akukumana nawo. Ngati abwana ali ndi amodzi okha, zigawo za Subordinate2-Subordinate4 zimangotaya malo osungirako (chinthu chofunika kwambiri). Kuwonjezera apo, taganizirani momwe abwana ali kale ndi omvera 4 - chimachitika ndi chiyani ngati atenga ntchito ina? Dongosolo lonse la tebulo lingapange kusintha.
Panthawiyi, lingaliro lachiwiri lowala nthawi zambiri limapezeka pamakalata opangira malemba: Sitikufuna kukhala ndi ndime imodzi ndipo tikufuna kulola kuchuluka kwa kusungirako deta. Tiyeni tiyese chinthu chonga ichi:
- Mtsogoleri
- Otsatira
Ndipo gawo loyang'anira limakhala ndi zolemba zambiri "mawonekedwe a" Mary, Bill, Joe. "
Njirayi ili pafupi, koma imakhalanso yochepa. Mbali yapansiyi imakumbukirabe osati ya atomiki. Kodi chimachitika ndi chiyani pamene tikufunika kuwonjezera kapena kuchotsa wogonjera? Tiyenera kuwerenga ndi kulemba zonse zomwe zili pa tebulo. Icho sichiri chovuta chachikulu mu izi, koma bwanji ngati mtsogoleri wina anali ndi antchito zana? Komanso, zimaphatikizapo ndondomeko yosankha deta kuchokera ku databuku m'mabuku amtsogolo.
Pano pali tebulo limene limakwaniritsa lamulo loyamba la 1NF:
- Mtsogoleri
- Otsatira
Pankhaniyi, aliyense ali ndi cholowa chimodzi, koma mameneja akhoza kukhala ndi zolemba zambiri.
2. Dziwani Chofunikira Chachikulu
Tsopano, nanga bwanji lamulo lachiwiri: pezani mzere uliwonse ndi mzere wapadera kapena mndandanda wazitsulo ( chofunikira chachikulu )? Mungathe kuyang'ana pa tebulo pamwambapa ndikupatseni kugwiritsa ntchito gawo lachinsinsi ngati chinsinsi chachikulu. Ndipotu, gawo lapansi ndilo woyenera kutsatila chinsinsi chofunikira chifukwa choti bizinesi yathu imayankha kuti aliyense ali ndi mtsogoleri mmodzi yekha. Komabe, deta yomwe tasankha kusunga mu tebulo lathu imapangitsa izi kukhala zosakwanira. Kodi chimachitika ndi chiyani tikamagwira ntchito wina dzina lake Jim? Kodi timasunga bwanji mgwirizano wake wothandizana naye mndandanda?
Ndibwino kugwiritsa ntchito chizindikiro chodziwika bwino (monga chizindikiritso cha ogwira ntchito) ngati chinsinsi chachikulu . Gome lathu lomaliza liziwoneka ngati izi:
- Mayi ID
- ID yochepa
Tsopano, tebulo lathu liri mu fomu yoyamba yachibadwa! Ngati mukufuna kupitiriza kuphunzira za normalization, werengani nkhani zina mndandandawu: