I-DB i ... Iindidi kunye neepropati zeenkcukacha

I-database iyigrafti, emele "database", okanye "database" (kuxhomekeke kumongo). Kule ngqaku, siza kuqwalasela ukuba ziphi, ziphi na ziphi kwaye zisetyenziswa phi. Kwakhona siza kuxubusha iDBMS kunye ne-DB - oku kuyafana okanye akunjalo.

I sigama

Idatha yolwazi luhlobo oluthile lovimba beenkcukacha. I-database nayo imodeli yolwazi enokukwazi ukuba neenkcukacha ezithile, kunye neemeko zokuba ziya kulandelwa. Ngamnye wethu wasebenza kunye ne-DB ubuncinane kanye, kodwa awakwazi ukuqiqa ngayo, umzekelo, xa ufaka umbuzo wokukhangela, siphendulela kwi-database ekululekileyo yolwazi oluthe ngqo.

I-DBMS yenye enye imfutshane, echazwa njenge "system management management system". Ngokuqhelekileyo, zimela izisombululo zesofthiwe ezahlukahlukeneyo onokuzihlela idatha yedatha. Oku kuthetha ukuzalisa ulwazi ngeenkcukacha, ukulungelelanisa, ukususa, ukulikopisha, ukuhlalutya, njalo njalo.

Iindidi zolwazi

Kwiingcamango zolwazi, ezininzi zeentlobo zazo ziyahluka. Kukho:

• Ulwalamano olunxulumene nolwalamano (oluvela kwisiNgesi, ubudlelwane ") olubhekiselele kubudlelwane kwaye luboniswe kwizinto ezidibeneyo. Ezi zilandelayo zifakwe ngendlela yamacwecwe, equlethe idatha yolwazi. Olu luhlobo oluqhelekileyo lweenkcukacha.
• Ulungelelaniso - uxhulumaniso kwizinga "ukhokho-inzala," "umphathi-phantsi."
• Inethiwekhi - isebe ukusuka kwimbono yangaphambili.
• I-oriented-oriented object, esebenza ngokuthe ngqo kunye neendlela ezihambelana neenkqubo (OOP).

Makhe siqwalasele ngamnye ngamnye ngeenkcukacha, ngokukhawuleza ukuyeka kwiingcamango ezisisiseko kunye neengcamango zolwazi.

DB - ingumqondiso?

Iinkcukacha zobudlelwane kunye nezikhundla zabo eziqhelekileyo azibangela ukuba kubekho ubunzima bokuqonda - ezi ziibhodi zolwazi. Ukucacisa, unokubiza uncedo olwaziwa kakhulu kwi-DBMS evela kwiMicrosoft- "Access", eyinxalenye yesicelo sabo esivamile se-applications.

Iitheyibhile zeenkcukacha zolwazi zineenkcukacha (imiqolo) kunye nemimandla (iikholomu). Iyokuqala iqulethe ulwazi oluchanekileyo, idatha, ekupheleni - inkcazo yento ekuthethwa ngayo ngokuthe ngqo. Ngokomzekelo, intsimi "igama", ukungena "Katerina".

Iintlobo zoxabiso zichazwe kwiindawo. Ziyakwazi ukubala, ukufuzisela, umhla, ixesha, njl. Ukongeza, iteksi nganye kufuneka ibe neenkalo eziphambili kwintsimi kuyo ngokuchanekileyo idatha idatha.

Kufuneka kuqondwe ukuba i-database ngokwayo ayikho itafile. Isitoreji singagcina ukusuka kwelinye ukuya kwiilafile eziliqela, kuxhomekeke kwisixa kunye neentlobo zolwazi.

Uqhagamshelwano phakathi kweetable

Ukubonelela ngekhonkco phakathi kwetafile kwi-DBMS, kukho izicwangciso zeedatha. Kukho uqhagamshelwano:

• "Ngamnye kuya komnye" -kuphela kokungena kwelinye itafile kufana nokungena nganye kwitafile.
• "Unye-kuninzi" kunye "abaninzi ukuya kuninzi". Ingxelo enye ingahambelana neethala eziliqela ezidibeneyo kanye. Kwaye ngokuphambene nxamnye (ukhetho lwesibini).
• "Uninzi kuninzi." Sekunzima ukuqiqa ukuba kule meko ininzi imiqolo yesinye itafile inokukhethwa kwimigca emininzi yoqhagamshelwano (olu lwalamano luhlelwe ngokusetyenziswa kwetafile ephakathi kunye nezikhonkwane ezimbini zolu hlobo olungentla).

Hambisa phezulu

Iinkcukacha ze-Hierarchical zineenkcukacha ezichanekileyo ngakumbi kunezihlobo. Zibonakaliswe ngokuthotyelwa ngokuthe ngqo. Kukho inxalenye yeengcambu - "phezulu", apho abaphantsi bancedisa khona - "iindlalifa" okanye "inzala". Idatha yolwazi oluphambili lwedatha luneenkcukacha kunye nesakhiwo somthi, apho i-node ngayinye inokuba nekhokho oyedwa kuphela.

Kukulungele ukusebenzisa lolu hlobo lokwakha izakhiwo zolwazi zesakhiwo esivele sinikezelweyo: umzekelo, isiseko sedatha yempi okanye umphathi wefayile. Ukungenakwenzeka kukuba akukho node yokuba nekhokho enye, kunye nobunzima beengcamango zesiseko sedatha.

Ukwandisa izixhumanisi

I-DBs Network iyisisombululo ekungabikho kobuhlanga, ekhankanywe ngentla apha. Ukwahlukana kuphela kwale hlobo ukusuka kwiphambano langaphambili kwakuxhamlwano "abaninzi kuninzi", oku kubonakala kule nkalo ukuba njengokuba ukhokho unokufumana izindlalifa ezininzi, ngoko ke, inzala, inokuvela kwiindawo eziliqela kanye.

Imbonakalo yeThabular yokubonisa

Nangona kunjalo ukuba iitheyibhile zidibaniswa ngokukodwa kunye nolwazi lwezentengiselwano, zombini izicwangciso zeendlela zokuhlala kunye nezicwangciso zentengiso zinokumelwa ngendlela yeetafile. Uhlobo oluphambili phakathi kwezi ntlobo ngokuchanekileyo ukwakhiwa kwesakhiwo: izihlobo, xa kuthelekiswa nezinye ezimbini, zikhululekile kakhulu kwaye zingalawulwa.

Udidi olujoliswe kuyo

Olu gqibela lubheka uhlobo-olujoliswe yintloko-lusezantsi. Yonke ngenxa yokuba ikhetheke kakhulu. Izakhiwo zeenkcukacha zeenkcukacha zolu daba lenza into kwaye zisebenze ngokuthe ngqo ngeelwimi zenkqubo ejoliswe kuyo. Ziye zaphuhliswa kwiminyaka engamashumi asibhozo ekhulwini lokugqibela kwaye azizange zithandwa kakhulu kodwa ngenxa yobunzima babo kwaye azikho ngejubane eliphezulu.