Chii Chinonzi Boyce-Codd Kazhinji Fomu (BCNF)?

by Mike Chapple

BCNF inopedza zvidzidzo uye inowedzera kuderera kwe data

Chinangwa che Boyce-Codd Normal Form (BCNF) ndechekuwedzera kudarika kwe data kuburikidza nekugadzira mapuranga nematafura ezvinyorwa zvezvekodzero kuitira kuti zviwanikwe nekugadziriswa kwemasvomhu. Nzvimbo yekuchengetedza zvinyorwa inowanikwa apo paine hukama hwehutano pakati pematafura uye kana matafura akatsanangura mitemo yekuita kuti dhesiyo iwedzere kushanduka uye kuchengetedza data.

Zvinangwa zvekuchengetedza mabhuku ehurumende ndezvekubvisa dambudziko rekudzivirira uye kuchengetedza kuvimbika kwepadhi kunonzwisisa.

A database yakarongeka kana data imwe chete isingachengetwi mune imwe tafura imwechete uye kana data yakangosangana chete yakachengetwa patafura.

Kubva Boyce-Codd Fomu Yakafanana

Kutevedzana katevedzana yemirayiridzo inovimbisa kuti databases inowanikwa. Iyi mitungamiri inotumidzwa semhando dzemazuva ose uye inotorwa kubva kune imwe kuburikidza nemashanu. Nhoroondo yezvekodzero inotsanangurwa seyakasikwa kana inosangana nemhando mitatu yekutanga: 1NF, 2NF, uye 3NF.

BCNF yakasikwa sechikwata chechitatu chemafomu chaiwo, kana 3NF, muna 1974 naRaymond Boyce naEdgar Codd. Varume vacho vakanga vachishanda kuti vape zvirongwa zvemashoko edzikisa zvigadziriswa zvisizvo nechinangwa chokuderedza nguva yekunyora. Chechitatu chimiro chechimiro chinobvisa zvinyorwa zvisingabatsiri pachigamba chekutanga pakuwedzera kusangana nemirayiridzo yekutanga uye yechipiri maitiro akare. BCNF, iyo dzimwe nguva inonzi inonzi 3.5NF, inosangana nezvose zvinodiwa zveNNN uye inoda kuti zvikwaniro zvevadzidzi vasave nehupi kune humwe unhu huri mutafura.

Panguva yezvisikwa zveBBCNF, Boyce aiva mumwe wevashandi vechiSwedish Shona Query Mutauro (SQL), iyo yakavandudza kuwanikwa kwekushandisa kuburikidza neCodd's relational model. Mumuenzaniso uyu, Codd yakaratidza kuti maitiro akaoma ezvinyorwa zvingaderedzwa, izvo zvaireva kuti mibvunzo inogona kuva yakasimba uye inochinja.

Kushandisa nheyo yake yekutsanangurira mashoko, Codd inotsanangura 1NF, 2NF, uye 3NF mirayiridzo. Akabatana naBamcece kuti vatsanangure BCNF.

Vadzidzi Keys uye BCNF

Chimwe chinhu chakakosha ndeyendarama kana kusanganiswa kwema column mutafura inoita chinhu chinoshamisa pane dhesi. Kubatanidzwa kwezvipimo kunogona kushandiswa kugona rekodhi rekodhiyo pasina kutarisa kune imwe dheseti. Tafura imwe neimwe inogona kuva nemakwikwi akawanda ekugadzirira, chero ipi zvayo inogona kukodzera seyiyo yekutanga. Tafura ine chinyorwa chimwechete chikuru.

Vadzidzi vanofanira kuva vakasiyana.

Ukama huri muBBCNF kana chirevo chega chega chiri chakakosha. Funga tafura yezvinyorwa inochengetedza ruzivo rwevashandi uye ine maitiro , , , uye . </p> <p> Mune tafura iyi, munda <Employee_Id> inotanga kutanga_name uye last_name. Saizvozvowo, tuple (<First_name>, <Last_name>) inosarudza <Employee_id>. </p> <table><tbody><tr><td> <strong>Dhiyabhorosi Id</strong> </td><td> <strong>Zita rokutanga</strong> </td><td> <strong>Zita rokupedzisira</strong> </td><td> <strong>Title</strong> </td></tr><tr><td> 13133 </td><td> Emily </td><td> Smith </td><td> Manager </td></tr><tr><td> 13134 </td><td> Jim </td><td> Smith </td><td> Shamwari </td></tr><tr><td> 13135 </td><td> Emily </td><td> Jones </td><td> Shamwari </td></tr></tbody></table><p><br> Nhengo yakakosha ye <a href="https://sn.eyewated.com/glossary-ye-common-common-terms/">database</a> iyi ndeye <Employee_Id> nokuti ndiyo chete yega inogona kushandiswa neimwe mutsara. </p> </div> <div class="amp-related-wrapper"> <h2>Alike posts</h2> <div class="amp-related-content"> <a href="https://sn.eyewated.com/kutaridzika-kwakavimbika-kuvimbika-kunogadzirisa-dhiyabhorosi/"> <amp-img src="https://exse.eyewated.com/pict/b3b60d775ada33d8-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kutaridzika-kwakavimbika-kuvimbika-kunogadzirisa-dhiyabhorosi/">Kutaridzika Kwakavimbika Kuvimbika Kunogadzirisa Dhiyabhorosi</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/kudzokorora-data-ne-sql-mibvunzo-kuzivisa-seti-statement/"> <amp-img src="https://exse.eyewated.com/pict/d9b95413c3b638a4-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kudzokorora-data-ne-sql-mibvunzo-kuzivisa-seti-statement/">Kudzokorora Data Ne SQL Mibvunzo: Kuzivisa SETI Statement</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/spreadsheets-vs-databases/"> <amp-img src="https://exse.eyewated.com/pict/124e90524a062ec7-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/spreadsheets-vs-databases/">Spreadsheets vs. Databases</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/chii-chinonzi-concession-database/"> <amp-img src="https://exse.eyewated.com/pict/a161f673732535a9-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/chii-chinonzi-concession-database/">Chii Chinonzi Concession Database?</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/kusarudza-gwaro-rakarurama-remicrosoft-sql-server-2012/"> <amp-img src="https://exse.eyewated.com/pict/ba4bc68cd2a52f76-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kusarudza-gwaro-rakarurama-remicrosoft-sql-server-2012/">Kusarudza Gwaro Rakarurama reMicrosoft SQL Server 2012</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/gadzira-tafura-nesql-server-2012/"> <amp-img src="https://exse.eyewated.com/pict/c64fed84b4c932c4-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/gadzira-tafura-nesql-server-2012/">Gadzira Tafura neSQL Server 2012</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/chii-chinonyanya-kukosha/"> <amp-img src="https://exse.eyewated.com/pict/b80e559b01543395-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/chii-chinonyanya-kukosha/">Chii Chinonyanya kukosha?</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/metadata-inokutevera-kwese-kwaunoenda/"> <amp-img src="https://exse.eyewated.com/pict/962323cace8632fa-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/metadata-inokutevera-kwese-kwaunoenda/">Metadata Inokutevera Kwese Kwaunoenda</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> <div class="amp-related-content"> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kufananidza-kudzora-statistical-model/">Kufananidza Kudzora Statistical Model</a></h3> <div class="amp-related-meta"> Software </div> </div> </div> </div> <div class="amp-related-wrapper"> <h2>See Newest</h2> <div class="amp-related-content"> <a href="https://sn.eyewated.com/kugovera-snow-leopard-os-x-10-6-files-ne-windows-7/"> <amp-img src="https://exse.eyewated.com/pict/dc5154dffb3f33e6-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kugovera-snow-leopard-os-x-10-6-files-ne-windows-7/">Kugovera Snow Leopard (OS X 10.6) Files ne Windows 7</a></h3> <div class="amp-related-meta"> Macs </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/shandisa-kuchengeta-kuchengetedza/"> <amp-img src="https://exse.eyewated.com/pict/a911461215b44084-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/shandisa-kuchengeta-kuchengetedza/">Shandisa Kuchengeta Kuchengetedza</a></h3> <div class="amp-related-meta"> Windows </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/iko-sony-fs7-ndiyo-yakanakisisa-kum-gun-kamera-pasi-pekuru-gumi/"> <amp-img src="https://exse.eyewated.com/pict/4e4c6ffca02235bc-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/iko-sony-fs7-ndiyo-yakanakisisa-kum-gun-kamera-pasi-pekuru-gumi/">Iko Sony FS7 ndiyo yakanakisisa-kum-gun kamera pasi pekuru gumi?</a></h3> <div class="amp-related-meta"> Product Reviews </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/kushandisa-vlc-media-player-kuenderera-mberi-kuronga-nziyo-dzakabva-jamendo/"> <amp-img src="https://exse.eyewated.com/pict/f66f71a715bc36db-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kushandisa-vlc-media-player-kuenderera-mberi-kuronga-nziyo-dzakabva-jamendo/">Kushandisa VLC Media Player kuenderera mberi Kuronga Nziyo Dzakabva Jamendo</a></h3> <div class="amp-related-meta"> Software & Apps </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/runhare-ethernet-cables-outdoors/"> <amp-img src="https://exse.eyewated.com/pict/f867476ba7954e4b-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/runhare-ethernet-cables-outdoors/">Runhare Ethernet Cables Outdoors</a></h3> <div class="amp-related-meta"> Internet & Network </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/ndeipi-ip-address-ye-facebook/"> <amp-img src="https://exse.eyewated.com/pict/1456f104070e3063-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/ndeipi-ip-address-ye-facebook/">Ndeipi IP Address ye Facebook?</a></h3> <div class="amp-related-meta"> Internet & Network </div> </div> </div> </div> <div class="amp-related-wrapper"> <h2>Sapid posts</h2> <div class="amp-related-content"> <a href="https://sn.eyewated.com/nzira-yokuwana-nayo-free-online-news/"> <amp-img src="https://exse.eyewated.com/pict/eec7ef1385813418-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/nzira-yokuwana-nayo-free-online-news/">Nzira Yokuwana Nayo Free Online News</a></h3> <div class="amp-related-meta"> Webhu & Tsvakurudzo </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/nzira-yokusunungura-kookies-necache-mu-chrome-browser/"> <amp-img src="https://exse.eyewated.com/pict/5d51994f9b223287-120x86.png" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/nzira-yokusunungura-kookies-necache-mu-chrome-browser/">Nzira Yokusunungura Kookies neCache mu Chrome Browser</a></h3> <div class="amp-related-meta"> Browsers </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/ko-ipad-inogona-kubudirira-ne-virus/"> <amp-img src="https://exse.eyewated.com/pict/25cdac8f6b3b33e4-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/ko-ipad-inogona-kubudirira-ne-virus/">Ko iPad Inogona Kubudirira Ne Virus?</a></h3> <div class="amp-related-meta"> IPad </div> </div> </div> <div class="amp-related-content"> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kugadzira-skins-ye-the-sims/">Kugadzira Skins ye "The Sims"</a></h3> <div class="amp-related-meta"> Gaming </div> </div> </div> <div class="amp-related-content"> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/kugumisa-3d-render-kuchengetwa-kwemavara-kubwinya-uye-migumisiro/">Kugumisa 3D Render: Kuchengetwa Kwemavara, Kubwinya, uye Migumisiro</a></h3> <div class="amp-related-meta"> Yatsva & Yotevera </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/nzira-yokubudirira-sei-neboka-rokunyora/"> <amp-img src="https://exse.eyewated.com/pict/f6f699d863333728-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/nzira-yokubudirira-sei-neboka-rokunyora/">Nzira Yokubudirira Sei Neboka Rokunyora</a></h3> <div class="amp-related-meta"> </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/smart-shoes-ichitsvaga-inoshandiswa-phenomenon/"> <amp-img src="https://exse.eyewated.com/pict/bebed9737ca73b6b-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/smart-shoes-ichitsvaga-inoshandiswa-phenomenon/">Smart Shoes: Ichitsvaga Inoshandiswa Phenomenon</a></h3> <div class="amp-related-meta"> Wearables </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/nzira-yokuona-unread-mail-in-outlook-express/"> <amp-img src="https://exse.eyewated.com/pict/cfb64c3e2a153d99-120x86.png" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/nzira-yokuona-unread-mail-in-outlook-express/">Nzira Yokuona Unread Mail In Outlook Express</a></h3> <div class="amp-related-meta"> Email & Messaging </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/woff-web-open-font-format/"> <amp-img src="https://exse.eyewated.com/pict/6f54141bc3e33686-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/woff-web-open-font-format/">WOFF Web Open Font Format</a></h3> <div class="amp-related-meta"> Web Design & Dev </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/cars-cheats-xbox-360/"> <amp-img src="https://exse.eyewated.com/pict/6229bdadd916345b-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/cars-cheats-xbox-360/">Cars Cheats - Xbox 360</a></h3> <div class="amp-related-meta"> Gaming </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/format-command/"> <amp-img src="https://exse.eyewated.com/pict/ef1030ef111d329f-120x86.png" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/format-command/">Format Command</a></h3> <div class="amp-related-meta"> Windows </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/digital-video-interface-dvi/"> <amp-img src="https://exse.eyewated.com/pict/c7ecf7be58b03276-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/digital-video-interface-dvi/">Digital Video Interface - DVI</a></h3> <div class="amp-related-meta"> Windows </div> </div> </div> <div class="amp-related-content"> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/zvaunofarira-bhuku-rekuvaraidza-kwekuzvarwa-kweaptlook-express/">Zvaunofarira Bhuku Rekuvaraidza Kwekuzvarwa kweAptlook Express</a></h3> <div class="amp-related-meta"> Email & Messaging </div> </div> </div> <div class="amp-related-content"> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/the-7-best-leather-iphone-cases-kutenga-muna-2018/">The 7 Best Leather iPhone Cases Kutenga muna 2018</a></h3> <div class="amp-related-meta"> Kutenga Mazano </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/5-matanho-ekugadzirisa-mapepa-matsva-nemahwendefa/"> <amp-img src="https://exse.eyewated.com/pict/a21890f227fe3131-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/5-matanho-ekugadzirisa-mapepa-matsva-nemahwendefa/">5 Matanho ekugadzirisa mapepa matsva nemahwendefa</a></h3> <div class="amp-related-meta"> Windows </div> </div> </div> <div class="amp-related-content"> <a href="https://sn.eyewated.com/iko-iko-faira-wakabvisa-zvechokwadi-here/"> <amp-img src="https://exse.eyewated.com/pict/98df7c827f53395a-120x86.jpg" width="120" height="86" layout="responsive" class="amp-related-image"></amp-img> </a> <div class="amp-related-text"> <h3><a href="https://sn.eyewated.com/iko-iko-faira-wakabvisa-zvechokwadi-here/">Iko Iko Faira Wakabvisa Zvechokwadi Here?</a></h3> <div class="amp-related-meta"> Webhu & Tsvakurudzo </div> </div> </div> </div></article> <footer class="amp-wp-footer"> <div class="amp-wp-footer-inner"> <a href="#" class="back-to-top">Back to top</a> <p class="copyright"> © 2024 sn.eyewated.com </p> <div class="amp-wp-social-footer"> <a href="#" class="jeg_facebook"><i class="fa fa-facebook"></i> </a><a href="#" class="jeg_twitter"><i class="fa fa-twitter"></i> </a><a href="#" class="jeg_google-plus"><i class="fa fa-google-plus"></i> </a><a href="#" class="jeg_pinterest"><i class="fa fa-pinterest"></i> </a><a href="" class="jeg_rss"><i class="fa fa-rss"></i> </a> </div> </div> </footer> <div id="statcounter"> <amp-pixel src="https://c.statcounter.com/12022999/0/02d06b5d/1/"> </amp-pixel> </div> </body> </html>