Okuqukethwe[Fihla][Bonisa]
- 1. Usho ukuthini ngeDatabase?
- 2. Usho ukuthini nge-DBMS?
- 3. Chaza izilimi ezahlukene ze-DBMS.
- 4. Bhala izinzuzo ezimbalwa ze-DBMS?
- 5. Yisho izithiyo zezinhlelo ezisekelwe kufayela ezijwayelekile ama-DBMS anazo phezu kwazo.
- 6. Usho ukuthini ngezakhiwo ze-ACID ku-DBMS?
- 7. Iyiphi indima i-SQL esebenza kuyo ku-DBMS?
- 8. Ingabe isikhala esingenalutho noma iqanda libalwa njengamavelu NULL kuzinqolobane?
- 9. Kuyini ngempela ukugcinwa kwedatha?
- 10. Isho ukuthini indawo yokuhlola ye-DBMS?
- 11. Chaza izendlalelo ezihlukahlukene zokukhishwa kwedatha ye-DBMS.
- 12. Kusho ukuthini "ukwenza kahle imibuzo" kuwe?
- 13. Ukumodela kobudlelwane bebhizinisi: kuyini?
- 14. Asho ukuthini amagama athi “ibhizinisi,” “uhlobo lwebhizinisi,” kanye “nesethi yebhizinisi” ohlelweni lokuphathwa kolwazi?
- 15. Kuyini ukuxhumana, futhi yiziphi izinhlobo zobudlelwano ezikhona ku-DBMS?
- 16. Iyini ngempela i-RDBMS?
- 17. Asho ukuthini amagama athi “intension” kanye “nesandiso” kusizindalwazi?
- 18. Yiziphi izindlela eziningi zokujwayelekile futhi lisho ukuthini igama elithi "normalization"?
- 19. Chaza ingidi. Umehluko omkhulu phakathi kwesikhiya esabelwe kanye nesikhiya esikhethekile ngesikhathi sokwenziwa kwesizindalwazi kufanele uchazwe.
- 20. Asho ukuthini amagama athi “normalization” nelithi “denormalilization”?
- 21. Chaza ukuhlukaniswa kwedathabhe kanye nokubaluleka kwakho.
- 22. Asho ukuthini kuwe amagama athi “proactive,” “retroactive,” kanye “ne-simultaneous update”?
- 23. Lisho ukuthini igama elithi “inkomba” kuwe? Chaza izinhlobo eziningi zezikhombisi.
- 24. Chaza ukuhluka phakathi kwamamodeli wedatha yenethiwekhi kanye nesizinda sesizindalwazi.
- 25. Chaza i-MongoDB.
- 26. Chaza ukuhluka phakathi kwesistimu ye-DBMS ye-2-tier kanye ne-3-tier.
- 27. Kusizindalwazi, lisho ukuthini igama elithi “hashing”?
- 28. Iyiphi indima eyenziwa umqondisi wesizindalwazi ku-DBMS?
- Isiphetho
Idatha ingatholakala noma kuphi emhlabeni! Ezimakethe zanamuhla, amabhayithi edatha angaphezu kuka-2.5 quintillion akhiqizwa usuku ngalunye.
Kubalulekile ukuthi sonke sihlaziye le datha futhi sinikeze imiphumela edingekayo sisebenzisa amasistimu okuphatha isizindalwazi (DBMS). Ngakolunye uhlangothi, ukuba nolwazi lwe-DBMS kwenza kube nokwenzeka ukusebenza njengomphathi wedathabheyisi.
Njengoba ufunda lokhu okuthunyelwe mayelana ne-DBMS Interview Questions, ngicabanga ukuthi usuvele uyayazi le mininingwane. Noma yimuphi umsebenzi wokuhlaziya idatha kufanele uqale ngokuqonda okuqinile kwezinhlelo zokuphatha isizindalwazi (DBMS).
Ukwakha amasistimu esizindalwazi asebenzayo kudinga ikhono lokuhlela, ukuhlola, ukudlula, nokwenza umqondo wedatha eningi.
Nansi imibuzo embalwa yenhlolokhono ye-DBMS ukukusiza ukuthi uphumelele kwinhlolokhono yakho elandelayo yomsebenzi futhi uthole isikhundla obusiphupha, noma ngabe usuwuqalile kakade umsebenzi wokuhlaziya idatha noma usaqala.
Imibuzo ephezulu yenhlolokhono ye-DBMS iqoqwe ohlwini ukuze kuzuze wena ukuze ikusize wenze inhlolokhono yakho futhi iqinise ukuqonda kwakho isihloko.
1. Usho ukuthini ngeDatabase?
Isizindalwazi siyiqoqo ledatha elakhiwe ngokunengqondo elingabuyekezwa, lifinyelelwe, futhi linakekelwe kalula. Noma yini ekhiqizwe ngomyalo wokudala iyinto egciniwe, futhi imininingwane yolwazi ivamise ukuhlanganisa amaqoqo amathebula noma izinto ezinokufakwa nezinkambu.
Ukufakwa okukodwa etafuleni kumelelwa i-tuple noma umugqa. Izingcezu ezibalulekile zokugcinwa kwedatha, ezihlinzeka ngemininingwane mayelana nesici esithile sethebula, ziyisibaluli noma ikholomu.
I-DBMS ibuyisa idatha kusizindalwazi isebenzisa imibuzo ehlinzekwe ngumsebenzisi.
2. Usho ukuthini nge-DBMS?
I-DBMS izinhlelo zesofthiwe ezikusiza ekudaleni nasekulawuleni idatha exhunywe ngokunengqondo.
Ukukubeka ngenye indlela, i-database management system (DBMS) isinika isikhombimsebenzisi noma ithuluzi lokwenza imisebenzi eyahlukene okuhlanganisa ukwakha isizindalwazi, ukwengeza idatha kuyo, ukuyisusa, ukushintsha idatha, nokunye.
I-Software ebizwa ngokuthi i-database management system (DBMS) yenza ukuthi idatha igcinwe ngendlela evikeleke kakhulu kunohlelo olusekelwe kufayela.
3. Chaza izilimi ezahlukene ze-DBMS.
Okulandelayo ngezinye zezilimi ezisetshenziswa ama-DBMS:
- I-DDL(Ulimi Lwencazelo Yedatha): Iziqondiso ezidingekayo ukuze kuchazwe isizindalwazi ziqukethwe kuyo. DALA, ALTER, DLA, TRUNCATE, REGAMA KABUSHA, njll. izibonelo ezimbalwa.
- I-DML(Ulimi Lokukhohlisa Kwedatha): Ihlanganisa imiyalo edingekayo ukuze usebenze nedatha kusizindalwazi. Izibonelo zifaka phakathi okuthi KHETHA, UKUBUYEKEZA, FAKA, SUSA, njll.
- I-DCL(Ulimi Lokulawulwa Kwedatha): Ihlanganisa imiyalo edingekayo ukuze ubhekane nezimvume zabasebenzisi kanye nokulawulwa kwesistimu yedathabheyisi. Isibonelo, i-Grant kanye ne-HOMUSA.
- I-TCL(Transaction Control Language): Ihlanganisa imiyalo okufanele isetshenziselwe ukuphatha ukuthengiselana kwesizindalwazi. Isibonelo, COMMIT, ROLLBACK, kanye ne-SAVEPOINT.
4. Bhala izinzuzo ezimbalwa ze-DBMS?
- Kuyenzeka ukuthi abasebenzisi abaningi bashintshisane ngedatha kusizindalwazi esifanayo ngesikhathi esisodwa. Ngaphezu kwalokho, lolu hlobo lokwabelana lwenza kube lula ukuthi abasebenzisi baphendule ngokushesha ezinguqukweni endaweni egciniwe.
- Kuyenzeka ukuthi abasebenzisi abaningi babuke idatha yesizindalwazi esifanayo ngesikhathi esisodwa.
- kunciphisa ukuphindaphinda kusizindalwazi ngokwethula isistimu ehlanganisa yonke idatha kusizindalwazi esisodwa.
- Uma kunesidingo, idatha ekusizindalwazi ingabuyiselwa futhi ikhophi yasenqolobaneni yedatha ingahlelwa ukuthi idalwe ngokuzenzakalelayo.
- Inika amandla ukuguqula ifomethi yedatha ngenkathi igcina ukwakheka kwazo zonke izinqubo zohlelo lokusebenza ezisebenzayo.
5. Yisho izithiyo zezinhlelo ezisekelwe kufayela ezijwayelekile ama-DBMS anazo phezu kwazo.
Siphoqeleka ukuthi siskene wonke amakhasi ohlelweni olujwayelekile olusekelwe kufayela njengoba kungekho indexing, okwenza ukufinyelela kokuqukethwe kudle isikhathi futhi kuvilapha.
I-redundancy kanye nokungahambisani ezinye izinkinga njengoba amafayela evamise ukufaka idatha engasasebenzi futhi eyimpinda, futhi ukushintsha eyodwa yakho kwenza wonke angahambisani.
Ukufinyelela idatha kuyinselele kakhulu ngezinhlelo zendabuko ezisekelwe kufayela njengoba idatha ingahlelekile. Okunye okungalungile ukuntuleka kokulawulwa kwe-concurrency, okuvimbela imisebenzi eminingi ekusebenzeni efayeleni elifanayo ngesikhathi esifanayo futhi esikhundleni salokho kuphoqelela isenzo esisodwa sokukhiya ikhasi lonke.
Izinhlelo zokuphatha isizindalwazi nazo zixazulule izinkinga ngezinhlelo zendabuko ezisekelwe kufayela ezihlanganisa ukuhlola ubuqotho, ukuhlukaniswa kwedatha, i-athomu, ukuphepha, nokuningi.
6. Usho ukuthini ngezakhiwo ze-ACID ku-DBMS?
Imihlahlandlela eyisisekelo okufanele ilandelwe ukuze kulondolozwe ubuqotho bedatha yizici ze-ACID zohlelo lokuphathwa kolwazi. Yilokhu abayikho:
- I-Atomicity - Ebizwa nangokuthi isimiso "konke noma lutho", i-atomicity ibamba ukuthi ukuhlolwa ngakunye kweyunithi eyodwa kwenziwa ngokuphelele noma cha.
- Ukungaguquguquki: Lesi sakhiwo sibonisa ukuthi idatha ekusizindalwazi ayishintshi ngaphambi nangemuva kokuthenga ngakunye.
- Isolation - Lesi sakhiwo sichaza ukuthi ukuthengiselana okuningi kungenzeka ngesikhathi esisodwa.
- Ukuqina - Lesi sakhiwo siqinisekisa ukuthi ukuthengiselana ngakunye kuqoshwa kumemori engaguquki uma sekuqediwe.
7. Iyiphi indima i-SQL esebenza kuyo ku-DBMS?
I-SQL imele Ulimi Lombuzo Ohlelekile, futhi umsebenzi wayo oyinhloko ukusebenzisana nedathabhesi yokuxhumana ngokufaka nokuvuselela/ukulungisa idatha.
8. Ingabe isikhala esingenalutho noma iqanda libalwa njengamavelu NULL kuzinqolobane?
Cha, inani elingu-NULL lihluke kakhulu kuziro nesikhala esingenalutho njengoba libonisa inani elabelwe, elingaziwa, elingatholakali, noma elingafaneleki, ngokuphambene nesikhala esingenalutho kanye noziro, ngamunye omele uhlamvu.
9. Kuyini ngempela ukugcinwa kwedatha?
Ukugcinwa kwedatha kuyinqubo yokuqoqa, ukukhipha, ukucubungula, nokungenisa idatha emithonjeni eminingana ukuze igcinwe kusizindalwazi esisodwa.
Inqolobane yedatha ingacatshangwa njengendawo emaphakathi lapho idatha isetshenziselwa ukuhlaziya idatha futhi igeleza isuka kumasistimu okwenziwayo kanye nezinye izingosi zolwazi ezihlobene.
A indawo yokugcina idatha iqukethe idatha yomlando evela enhlanganweni esetshenziselwa ukuthuthukisa ukwenziwa kwezinqumo ngaphakathi kwenkampani.
10. Isho ukuthini indawo yokuhlola ye-DBMS?
Indlela ye-Checkpoint isusa wonke amalogi adlule ohlelweni futhi iwalondoloze unomphela kudivayisi yokugcina.
Amasu amabili angasiza i-DBMS ukuthi ilulame futhi igcine izimfanelo ze-ACID ihlanganisa ukulondoloza amakhasi ethunzi nokugcina irekhodi lomsebenzi ngamunye. Izindawo zokuhlola zibalulekile kundlela yokutakula esekelwe kulogi.
Irekhodi lerekhodi lomsebenzi lingasetshenziselwa ukubuyisela yonke idatha ezibophezele kuze kufike isikhathi sokuphahlazeka ezindaweni zokuhlola, okungamaphuzu amancane lapho injini yolwazi ingalulama khona ngemva kokuphahlazeka.
11. Chaza izendlalelo ezihlukahlukene zokukhishwa kwedatha ye-DBMS.
Ukukhishwa kwedatha kufihla ulwazi olungabalulekile kumsebenzisi ukuze kuthuthukiswe ukusebenzisana okungenazihibe. Izendlalelo ezintathu zokuthatha zikhona:
- Izinga Lomzimba: Izinga elincane kakhulu lokukhipha lichaza ukugcinwa ngokomzimba kwedatha enkumbulweni. Zombili izindlela zokufinyelela ezilandelanayo nezingahleliwe zingasetshenziswa ukufinyelela idatha. Izihlahla ze-B+ nezindlela ze-hashing zisetshenziselwa ukuhlela amafayela.
- Ileveli Enengqondo: Izinga lapho idatha igcinwa khona ngendlela yamathebula. Ukwengeza, izakhiwo eziyisisekelo zisetshenziselwa ukugcina ukuxhumana phakathi kwezakhi ezahlukene.
- Buka Izinga: Izinga eliphakeme kakhulu lokukhipha. Ingxenye kuphela yesizindalwazi sangempela, emelwe imigqa namakholomu, etholakala kubasebenzisi. Ukubuka okuningi kwesizindalwazi esifanayo kuyacatshangwa. Abasebenzisi abaziswa ngemininingwane yokugcinwa nokusetshenziswa.
12. Kusho ukuthini "ukwenza kahle imibuzo" kuwe?
Isinyathelo sokuthuthukisa umbuzo sithola isu lokuhlola elinezindleko eziphansi eziqanjiwe. Lesi sigaba siba sibalulekile uma kukhona ama-algorithms namasu amaningana atholakalayo ukwenza inkinga efanayo.
Okulandelayo ezinye izinzuzo zokuthuthukisa imibuzo:
- Okukhiphayo kulethwa ngokushesha okukhulu
- Yehlisa i- ubunkimbinkimbi besikhathi kanye nesikhala
- Imibuzo eminingi ingacutshungulwa ngesikhathi esifushane.
13. Ukumodela kobudlelwane bebhizinisi: kuyini?
Le ndlela yokwakhiwa kwesizindalwazi isebenzisa imidwebo ukuveza izinto zangempela emhlabeni wangempela njengezinhlangano futhi ibonise ubudlelwano bazo. Le ndlela yenza kube lula ukuthi ithimba le-DBA liqonde i-schema.
14. Asho ukuthini amagama athi “ibhizinisi,” “uhlobo lwebhizinisi,” kanye “nesethi yebhizinisi” ohlelweni lokuphathwa kolwazi?
Ibhizinisi: Into yomhlaba wangempela ithathwa njengebhizinisi uma inezinto ezihambisana nezici zayo ezithile. Ngokwesibonelo, umfundi, isisebenzi, noma uthisha ufanekisela ibhizinisi.
Uhlobo Lwebhizinisi: Uhlobo lwebhizinisi luchazwa njengeqembu lamabhizinisi anezici ezifanayo. Uhlobo lwebhizinisi lumelelwa ithebula elixhunyiwe elilodwa noma amaningi kusizindalwazi. Kuyenzeka ucabange ngohlobo lwebhizinisi noma izibaluli njengesici esikhomba ngokuqondile ibhizinisi. Umfundi, isibonelo, ufanekisela into enezici ezifana ne-student ID, igama lomfundi, njll.
Isethi Yebhizinisi: Wonke amabhizinisi akusizindalwazi sohlobo oluthile lwebhizinisi aqoqwa ndawonye njengesethi yebhizinisi. Isibonelo, isethi yebhizinisi iqoqo labo bonke abafundi, amalungu ezisebenzi, othisha, njalonjalo.
15. Kuyini ukuxhumana, futhi yiziphi izinhlobo zobudlelwano ezikhona ku-DBMS?
Ku-DBMS, ubudlelwano yisimo lapho izinhlangano ezimbili zixhumene komunye nomunye. Kulokhu, ithebula lokhiye wangaphandle linereferensi kukhiye oyinhloko welinye ithebula.
Uhlu olulandelayo luhlanganisa izinhlobo eziningi zobudlelwano ezitholakala ku-DBMS:
- Ubudlelwano Okukodwa-kukodwa: Leli gama lisetshenziselwa ukuchaza ubudlelwano phakathi komugqa owodwa kuThebula A kanye nomugqa owodwa kuThebula B.
- Ubudlelwano Okukodwa-kuningi: Kusetshenziswa uma kunokuhlobana phakathi komugqa owodwa kuThebula A kanye nemigqa eminingi kuThebula B.
- Ubudlelwano Obuningi-kuya-Obuningi - Kusetshenziswa lapho inombolo enkulu yemigqa kuthebula A ingaxhunywa enanini elikhulu lemigqa kuthebula B.
- Ubudlelwane Obuzibheka Ngayo - Busetshenziswa lapho irekhodi elikuthebula A lixhunywe kwelinye irekhodi kuthebula elifanayo.
16. Iyini ngempela i-RDBMS?
I-RDBMS, noma izinhlelo zokuphatha isizindalwazi esihlobene, isifinyezo salezi zinhlelo. Isetshenziselwa ukulandelela izinkomba zethebula namarekhodi edatha.
Ama-RDBMS ayisethi engaphansi yezinhlelo zokuphatha isizindalwazi ezisebenzisa isakhiwo ukuze kutholwe futhi kutholwe ulwazi mayelana nezinye izinto zesizindalwazi. Uhlelo lokuphathwa kwesizindalwazi esihlobene (RDBMS) lwenza kube lula ukubuyekeza, ukufaka, ukususa, ukuhlela, nokuphatha imininingwane yokuxhumana.
Isikhathi esiningi, i-RDBMS isebenzisa ulimi lwe-SQL njengoba isebenziseka kalula futhi isetshenziswa njalo.
17. Asho ukuthini amagama athi “intension” kanye “nesandiso” kusizindalwazi?
Umehluko omkhulu phakathi kwenhloso nesandiso kusizindalwazi umi kanje:
Inhloso: Inhloso, ngezinye izikhathi ebizwa ngokuthi i-schema yesizindalwazi, isetshenziselwa ukuchaza incazelo yesizindalwazi. Isungulwa ngesikhathi sokwakhiwa kwesizindalwazi futhi ngokuvamile ayishintshi.
Isandiso: Ngakolunye uhlangothi, isandiso siyisilinganiso senani lenani lama-tuple kusizindalwazi nganoma yisiphi isikhathi esisodwa. Uma ama-tuples edalwa, elungiswa, noma esuswa kusizindalwazi, isandiso, esaziwa nangokuthi isifinyezo sesizindalwazi, silokhu sishintsha inani.
18. Yiziphi izindlela eziningi zokujwayelekile futhi lisho ukuthini igama elithi "normalization"?
Ukwenza ngokwejwayelekile inqubo yokuhlela idatha ukuze kuvinjelwe ukuphindaphindeka kwedatha nokungadingeki. Izigaba eziningana zokujwayela ziyalandelana futhi zibizwa ngokuthi amafomu avamile. Amafomu alandelayo ancike komunye nomunye.
Amafomu amathathu okuqala ajwayelekile ami kanje.
I-NF-1, noma Ifomu Lokuqala Elivamile, imigqa ngaphandle kwamaqembu aphindaphindiwe
I-2NF imele Ifomu Lesibili Elijwayelekile. Inani ngalinye lekholomu esekelayo (elingewona ukhiye) lincike kuwo wonke ukhiye oyinhloko.
I-Three-Normal-Form (3NF) incike kuphela kukhiye oyinhloko futhi ayincikile kunoma imaphi amanye amanani ekholomu asekelayo (okungewona okhiye).
Futhi unamafomu avamile aphezulu, afana ne-BCNF, ngaphezu kwalawa.
I-BNCF – Uhlobo oluyinkimbinkimbi noludingayo lwe-3NF lubizwa ngokuthi 3.5NF. Ithebula kufanele libe ku-3NF futhi lihambisane nomthetho we-BCNF wokuthi u-A kufanele abe ukhiye omkhulu wethebula wanoma yikuphi ukuncika okusebenzayo kokuthi A->B.
19. Chaza ingidi. Umehluko omkhulu phakathi kwesikhiya esabelwe kanye nesikhiya esikhethekile ngesikhathi sokwenziwa kwesizindalwazi kufanele uchazwe.
Ilokhi yedathabheyisi isilinganiso sokuvikela esivimbela abasebenzisi besizindalwazi ababili noma ngaphezulu ukuthi babuyekeze ucezu olwabiwe lwedatha ngesikhathi esisodwa.
Akekho omunye umsebenzisi wesizindalwazi noma iseshini engahlela idatha kuze kube yilapho isikhiye sikhishwa kusizindalwazi esithile lapho umsebenzisi oyedwa wesizindalwazi noma iseshini ithole ukukhiya.
Ukhiye Wabiwe: Ukufunda into yedatha kudinga ukukhiya okwabelwana ngakho, futhi imisebenzi eminingi ingabamba ukukhiya entweni efanayo yedatha ngaphansi kwesikhiya esabiwe. Izakhi zedatha ekukhiyweni okwabelwana ngazo zingafundwa ngokwenziwe okuningi.
Ukukhiya okukhethekile: Noma yikuphi okwenziwayo mayelana nokwenza umsebenzi wokubhala kunokhiye, owaziwa ngokuthi ukhiye okhethekile. Lolu hlobo lokukhiya luvimbela ukuthengiselana okuningi, luvimbela noma yikuphi ukungafani kusizindalwazi.
20. Asho ukuthini amagama athi “normalization” nelithi “denormalilization”?
Inqubo yokujwayela ibandakanya ukuhlukaniswa kwedatha ibe amathebula amaningi ukuze kuncishiswe ukungasasebenzi. Ukujwayela kuphumela ekusetshenzisweni okukhulu kwesikhala sediski futhi kwenza kube lula ukulondoloza ubuqotho besizindalwazi.
I-Denormalization iphambene nokujwayelekile njengoba ihlanganisa amathebula ajwayelekile abe yithebula elilodwa ukuze kusheshiswe ukubuyisa idatha. Ngokuphenyisisa ukwenza kube okujwayelekile, ukusebenza kwe-JOIN kusenza sikwazi ukukhiqiza ukumelelwa okungajwayelekile kwedatha.
21. Chaza ukuhlukaniswa kwedathabhe kanye nokubaluleka kwakho.
Isizindalwazi esinengqondo sihlukaniswa sibe amabhizinisi ahlukene, aziqukezele ngokwawo ngenqubo yokuhlukanisa idatha, okuthuthukisa ukutholakala, ukusebenza, nokuphathwa.
Okulandelayo ezinye zezizathu zokuthi kungani ukuhlukaniswa kwedatha kubalulekile:
- Ithuthukisa ukusebenza kahle kwemibuzo
- Ikuvumela ukuthi ufinyelele izingxenye ezibalulekile zengxenye ethile
- Idatha ingagcinwa endaweni yokugcina evilaphayo, engabizi.
22. Asho ukuthini kuwe amagama athi “proactive,” “retroactive,” kanye “ne-simultaneous update”?
Ukuvuselelwa Okuqhubekayo: Ngaphambi kokuthi isizindalwazi sisebenze emhlabeni wangempela, lokhu kulungiswa kwenziwa kuyo.
Ukuvuselelwa Okubuyiswayo: Ngemva kokuthi isizindalwazi sisebenza emhlabeni wangempela, lezi zinguquko ezibuyiselwayo zenziwa kuyo.
Isibuyekezo Esikanye Ngasikhathi sinye: Lezi zinguquko zenziwa kusizindalwazi ngesikhathi esifanayo lapho ziqala ukusebenza emhlabeni wangempela.
23. Lisho ukuthini igama elithi “inkomba” kuwe? Chaza izinhlobo eziningi zezikhombisi.
Ikhesa yinto egciniwe esekela ukukhohliswa kwedatha yomugqa ngomugqa futhi imele isethi yomphumela.
Lezi izinhlobo eziningana zezikhombisi:
- Ikhesa engasho lutho: Lolu hlobo lwekhesa lumenyezelwa ngokushesha nje uma i-SQL isetshenziswa. Umsebenzisi akaziswa ngesimemezelo sekhesa kulokhu.
- Ikhesa ecacile: Njengoba icubungula umbuzo ngemigqa eminingana, lolu hlobo lwekhesa luchazwa yi-PL/SQL.
24. Chaza ukuhluka phakathi kwamamodeli wedatha yenethiwekhi kanye nesizinda sesizindalwazi.
Idatha ihlelwa yaba ama-node kulokho okufana nesihlahla ku-hierarchical database paradigm. I-node ingaba nenodi yomzali eyodwa kuphela exhunywe kuyo.
Njengomphumela, idatha yale modeli inokuxhumana okukodwa kuya kokuningi. I-Document Object Approach (DOM), evame ukusetshenziswa ezipheqululini zewebhu, iyisibonelo esiyinhloko sale modeli.
Okuhlukile okuthuthukisiwe kwemodeli ye-hierarchical imodeli yesizindalwazi senethiwekhi. Idatha ihlelwa ngendlela efanayo nesihlahla kulesi sibonelo. I-node eyodwa yengane, nokho, ingase ixhunywe kumanodi omzali amaningana.
Isixhumanisi sokuningi kuya kokuningi siyakhula phakathi kwamanodi wedatha njengomphumela. Imininingo egciniwe yenethiwekhi ihlanganisa Isitolo Sedatha Esihlanganisiwe (IDS) kanye ne-IDMS (Uhlelo Oludidiyelwe Lokuphathwa Kwedathabhesi).
25. Chaza i-MongoDB.
I-MongoDB iyisizindalwazi esivulekile, esingahlobene, esingahlelekile. Idatha yakho igcinwa kumaqoqo enziwe amadokhumenti ngamanye kusizindalwazi sethu esigxile kumadokhumenti.
Idokhumenti ku-MongoDB iyinto enkulu ye-JSON engenasakhiwo esithile noma i-syntax. Amadokhumenti e-JSON amelwe yi-MongoDB ngefomethi efakwe ikhodi kanambambili ebizwa ngokuthi i-BSON.
26. Chaza ukuhluka phakathi kwesistimu ye-DBMS ye-2-tier kanye ne-3-tier.
Igama elithi "i-architecture enezigaba ezimbili" ibhekisela ekwakhiweni kweseva yeklayenti lapho izinhlelo zokusebenza ezisebenza kumakhasimende zixhumana ngokuqondile nesizindalwazi esisebenza kumaseva ngaphandle kokusetshenziswa kwanoma iyiphi i-middleware.
Idizayini ye-3-tier ihlanganisa isendlalelo esengeziwe phakathi kweklayenti neseva ukuze unikeze abasebenzisi nge-graphic interface yomsebenzisi nokwenza isistimu ivikeleke kakhulu futhi ifinyeleleke. Ngalolu hlobo lokuklama, uhlelo lokusebenza oluseceleni kweklayenti lusebenzisana nohlelo lokusebenza oluseceleni kweseva, ebese likhuluma nohlelo lwedathabheyisi.
27. Kusizindalwazi, lisho ukuthini igama elithi “hashing”?
Uchungechunge lwezinhlamvu lusheshiselwa kukhiye noma inani elimele iyunithi yezinhlamvu yoqobo kodwa ngokuvamile lilungiswa libe nobude obuncane. Njengoba ukuthola into kusetshenziswa ukhiye we-hashi omfushane kunevelu yoqobo kushesha, i-hashing isetshenziselwa ukukhomba nokuthola izinto kusizindalwazi.
28. Iyiphi indima eyenziwa umqondisi wesizindalwazi ku-DBMS?
I-Database Administrator (DBA) inezindima ezibalulekile ezilandelayo ku-DBMS:
- Ukusetha nokufaka imininingwane yolwazi
- Ukuthuthwa kwedatha
- Ukuhlola ukusebenza
- Ukuhlela nokusebenzisa izinyathelo zokuphepha
- Ukutholwa nokugcinwa kwedatha
- Ukuxazulula
Isiphetho
Ukuqoqwa kwemibuzo nezimpendulo ze-DBMS kuhlinzekwe njengereferensi ukuze labo abangase bakwazi ukuyiqonda le mibuzo ngokushesha futhi kalula.
Sengiphetha, sihlaziye imibuzo ephezulu yenhlolokhono ye-DBMS evame ukubuzwa ezinhlanganweni.
shiya impendulo