A baninzi-to-ezininzi: Umzekelo e Access, kwi SQL. Indlela yokwenza ezininzi-to-?

Zonke DBMS (inkqubo yolawulo database) , kukho iindidi ezininzi ubudlelwane phakathi ezitafileni. Phakathi kwabo one-to-one, omnye-to-ezininzi, abantu abaninzi-to-one (abanye bavame ukuchonga ezi ntlobo zimbini zibe enye) kwaye abaninzi-to-abaninzi. Umzekelo yokugqibela, yaye ingcaciso isicelo kwayo zolwazi ezahlukeneyo, ezifana Access okanye SQL, eza kuxutyushwa kweli nqaku.

definition

Abaninzi-to-nabaninzi ichazwa njenge umdlalo nayiphi na iikopi yomnye essences zonke ezinye iimeko. Ngamanye amazwi, intsimi ngalinye (okwesibini) itheyibhile yokuqala enxulumene onke amasimi yesibini (lokuqala).

Esi sikimu ibonisa ngokucacileyo undoqo kulo mtshato.

ezininzi-to-ezininzi ubudlelwane ingasetyenziswa nini?

Umzekelo ezininzi-to-ezininzi - iqela umfundi kunye neqela lootitshala. Umfundi ngamnye ufunda ngexesha kanye oonjingalwazi embalwa, owathi yena, ukunika iintetho abafundi eziliqela. Kulo mfanekiso ubonisa umahluko phakathi-one-to-ezininzi abaninzi-to-abaninzi.

ubudlelwane-to-amaninzi kudla kuyimfuneko ukulungiselela zolwazi ezinkulu-isikali, imizekelo ezincinane ezichaza ezisetyenziswa ngokuqhelekileyo kuphela iinjongo zemfundo, eneneni, xa kusenziwa ujika ukuba amaqumrhu ngakumbi nkcukacha kuvimba weenkcukacha kunye nobudlelwane phakathi kwabo - kokukhona ukuba nokwenzeka abanaluncedo rhoqo ukuze abaninzi-to-abaninzi.

Indlela yokwenza ezininzi-to-?

Imizekelo ulwalamano echaphazelekayo iya kudityaniswa kule khosi senqaku, kodwa kubalulekile ukuqonda nje ukuba kuyintoni na, kodwa kananjalo nokusebenzisa iinkqubo njani. Iinkcukacha zale nkqubo kuxhomekeke ngqo kwi-database ezikhethiweyo ukuba lo msebenzi, ngoxa isimiso esifanayo kubo bonke.

Microsoft Access

software Office ukusuka 'Microsoft "waziwa kwimarike software ye kangangethuba ixesha elide. It iza umhleli wokubhaliweyo Worfd, Excel iprosesa tabular kunye nezinye ukubayinxalenye kumnombo 'i-ofisi ". Ungangena (funda njenge "Access", inguqulelo wokoqobo - "ukufikelela") ukuthenga kwaye wahlukile 'koogxa' yakhe. Kuyanconywa ukuba kuthenga, Kakade ke, zekhompyutha mvume, kodwa akukho mfihlakalo ukuba indlela anokufumaneka repack pirated kwi web enkulu, ngokohlobo iifayile rhoqo, okanye Imilambo izandla. "Microsoft Access" ifumaneka nkqu kwindibano ephathwayo. Akudingi ufakelo kunye naziphi na izakhono ezizodwa ukusebenza nge PC, oko ifanele lokukhetha ukuba software akayi kusetyenziswa ixesha elide yaye ngokufuthi.

Ukusuka umongo kucacile ukuba "Microsoft Access" - i inkqubo yolawulo ledatha. Ke kaloku omnye ethandwa kakhulu. Kuyinto ezinobume, nto leyo ithetha ukuba sisekelwe phezu ubhalo imodeli data, leyo ngexesha umsebenzi wakhe libhekisela ithiyori iseti kunye lokuqala-order logic. Abaninzi-to-nabaninzi kwi Ufikelelo (imizekelo iza kunikwa ingcaciso) iqaphelwa kakhulu, ilula kakhulu. Kukuqonda oko.

Kukho iitafile ezimbini ..

Ukuze ukuba zizakhele nantoni na entsha, thatha senditshilo ukucacisa umzekelo abaninzi-to-abaninzi kulifunda abafundi. Kufuneka wenze itafile "abafundi" yaye itafile "Ootitshala." Zombini yokuqala neyesibini ezi izitshixo zaseprayimari. Kwakhona kufuna kwenye itafile, eyiphi imihlaba ngenxa yokudibanisa iimeko zezi nkampani zimbini - izitshixo iitafile yokuqala neyesibini.

Xa siqwalasela umzekelo ezahlukeneyo: masithi, abadlali kunye neqela (unikwe into yokuba iqela ubuncinane enye abadlali ukudlala amaqela ezahlukeneyo, yaye ngamnye ubunjwe abadlali abalishumi elinanye), nakha uqhagamshelwano akayi kutshintsha. Kananjalo kuya kufuneka iitafile ezintathu. Kwezi, "ekhatywayo" yaye "Iqela" njengoko ezingundoqo omnye eliphakathi.

scheme data

Ubudlelwane phakathi amacwecwe database "Microsoft Access" usebenzisa i tab "Scheme Data". Iqela lenjongo libonisiweyo yongezwe onke amaziko (kulo mzekelo, zonke zontathu iitafile). Yenza i-one-to-ezininzi ubudlelwane-to-emininzi iza kusetyenziswa ulwalamano ezimbini, phakathi inqununu ( "abafundi" yaye "Ootitshala ') kunye netafile mvelo. Ukuze wenze oku, umele uqhagamshelo amaqhosha zaseprayimari ngokulandelelana.

Lo mzekeliso ngentla ibonisa indlela "yesekethe data 'tab (Relathionships). Inani yongezwe kwibhodi itafile ngokungenammiselo. Indawo adjustable ngokupheleleyo ngumsebenzisi.

SQL

Database Design kwi SQL - umsebenzi nzima kunokuba "Access". Ukuba imveliso maykrosoftovskih iqhelene ngokupheleleyo bume ofisi, unendawo enkulu kunye, kunye ukukhululwa nganye kwaye nokuhlaziya zonke andisiweyo ukusebenza, kodwa kwangaxeshanye lula ukuba ujongano lomsebenzisi elula, SQL - yinto ulwimi lokuprograma non-procedural eyahlukileyo, ngayo kumaqonga ahlukeneyo unako ukusebenza zolwazi. I-software ezaziwayo-kakuhle lo msebenzi: Oracle I SQL yam kunye DB2 (a popular, kodwa hayi kuphela elolu hlobo). Nangona kukho inyaniso yokuba ngamnye kubo ubuqili zalo bokuqonda, ulwimi SQL yi "emanyeneyo 'zabo. Ngokufunda ukusebenza ubuncinane omnye kubo, ukujongana nabanye kuya kuba lula kakhulu.

Dala, ukugcwalisa kunye nezenzo ngqo kwiziko ledatha ezikhoyo SQL kwakufuneka ngokusebenzisa ikhowudi ekhethekileyo okanye zeempendulo. Noko ke, abo sele owenza kwicandelo 'abaninzi-to-ezininzi ", umzekelo apho kule ulwimi lokuprograma unikwa ngezantsi, kufuneka bayazi imithetho esisiseko kunye nemigaqo yolwimi SQL.

Umgaqo ekudaleni abaninzi-to-ezininzi

ukufikelela elide ukuba neentloni ezinye kwaye "kuyikhulula enkungwini", kodwa enyanisweni umgaqo ukuphunyezwa lonxibelelwano kuhlala enye. Ukuze ubhale ubudlelwane-to-abaninzi sele uphunyeziwe practice, hayi nje kuphela kweli "Access", kodwa ke SQL, kufuneka udale okokuqala iitafile isiseko ezimbini enye - eliphakathi. Ngokufanayo, oko enesitshixo: uhlobo ezingundoqo kwiinkalo eziphambili, nganye ibhalwe kwetafile Ukuhlanganisa. Nto leyo ethetha ukuba ubudlelwane SQL-abaninzi-to-abaninzi azahlukanga kuyaphi ukusuka 'Access ".

Ukusetyenziswa konxibelelwano

Ukumilisela ngendlela abaninzi-to-ezininzi script SQL usebenzisa amaqhosha yangaphandle (iqhosha langaphandle) ezifanayo kwiqhosha ezingakhutshelwanga ezikolu luhlu engundoqo. Iziphumo kunye nawo onke amasimi xa kuyilwa kunye / okanye nohlelo.

Indima ezininzi abaninzi-to-

Ngokubanzi, ulwalamano phakathi amaqela kuvimba ezisetyenziselwa ukuthembeka kolwazi egcinwe kuzo. Kuphela database oluyilwe kakuhle zonke unxulumano eziyimfuneko kuqinisekisa yokugcina ekhuselekileyo, amava lomsebenzisi kwaye isakhiwo ukumelana kwiimpembelelo zangaphandle kunye notshintsho. Ngokuqhelekileyo, ukuba uvimba iqulethe data kwi umbutho yonke, inkampani okanye niqinile, iqulathe uluhlu lwamaqumrhu neemeko ezahlukeneyo.

Oku kuthetha ukuba lokulungisa ezi zicwangciso ( "Access") okanye zeempendulo zokubhala (kwi "Oracle" okanye "DiBiTu") liya kuba khona ubuncinane enye abaninzi-to-abaninzi. Umzekelo SQL, isoloko isetyenziswa kuqeqesho khosi "sedata Umbutho" - DB King.

Base of data zikaKumkani

Le database Uqeqesho lulwazi malunga uKumkani corporation. Phakathi iitafile:

• abasebenzi benkampani - iqulethe le ID yomqeshwa, igama lokugqibela, igama lokuqala kunye ophakathi lokuqala (focus on amagama amazwe), kwakhona ikhowudi umqeshi kunye nomqeshwa ahlala indawo, umhla ukwamkelwa mveliso abafumana imivuzo yabo ikhomishini enikiweyo, ikhowudi isebe;
• amasebe bemibutho - phakathi ngokwemihlaba itafile babe ikhowudi kunye negama zesebe, ngokunjalo ikhowudi indawo yayo;
• amasebe ukubekwa, nto leyo equka ngokungenisa ulwazi malunga nokubekwa ikhowudi kunye negama lomzi;
• isikhundla kwinkampani - isithebe esincinci kwimihlaba ezimbini post ikhowudi kunye negama layo elisemthethweni;
• Iinkampani-abathengi - emasimini: ikhowudi kunye igama lomthengi, idilesi, isixeko, nephondo, ikhowudi yeposi kunye nekhowudi yommandla, inombolo yefowuni, umphathi wenkonzo ikhowudi umthengi, adunyiswe ngumthengi kunye izimvo (comments kunye namanqaku);
• izivumelwano zentengiso, equlethe ikhowudi kunye nomhla kwesivumelwano, ikhowudi umthengi, nomhla wokuziswa kunye nemali iyonke lesivumelwano;
• Izenzo yokuthengisa - isenzo ikhowudi kunye nekhowudi kwesivumelwano, equka isenzo, ikhowudi imveliso, ixabiso layo, ubungakanani yathengwa kwaye lilonke ixabiso lokuthenga;
• I impahla - igama ikhowudi imveliso;
• ixabiso - ikhowudi imveliso leyo, wazisa kuye ixabiso, elona xabiso lisezantsi kunokwenzeka, umhla ukusekwa kunye nomhla ixabiso ukurhoxiswa le.

itheyibhile Small ezikhoyo apho amasimi akukho ngaphezulu kwe ezimbini okanye ezintathu ezinxulumene ukuya itafile i-one-to-one okanye one-to-abaninzi.

Scale itafile efanayo, ezifana 'abasebenzi inkampani "," inkampani-abathengi "," izivumelwano ukuthengisa' 'nezenzo intengiso' zinxulumene kunye namaqumrhu eziliqela, ezinye - ngoncedo "abalamleli" ubudlelwane-to-abaninzi. Uluhlu "nabathengi inkampani" ngokwaso umlamleli, njengoko hlobo, ngokuba baninzi asendle, athathwe kwezinye iitafile kunye iqhosha langaphandle. Ukongeza, izinga kunye database ulwalamano "UKumkani Corporation" kukuba zonke buhlobo zingqamene ezingenakwahlulwa kunye nabanye kwaye zichaphazela omnye komnye. Ukutshatyalaliswa ubuncinane omnye kubo kuya kukhokelela ekutshatyalalisweni ingqibelelo yonke ledatha.

bokuqonda ezibaluleke

Xa zisebenzisa abaninzi-to-ezininzi, kungakhathaliseki ukuba kusetyenziswa apho ulawulo ledatha lesistim, kubalulekile ukumisela izitshixo ezichanekileyo ngayo ziya kuqulunqwa sengqondo. Ngokungachanekanga laphumeza uxhulumaniso engazifezekisi injongo yayo - oko kukuthi, ukuqinisekisa ukuthembeka itafile, yaye ngenxa yoko, endaweni intuthuzelo ezilindelekileyo, umsebenzisi uya kwamkela, kwelinye icala, ngokuphazamisa kunye neengxaki ezongezelelweyo, ingakumbi lubonakala ngexesha ngokugcwalisa iitafile ukuhlela idatha yazo.