Ubale Nawonso achichepere. Chiphunzitso cha Nawonso achichepere ubale

Zikamera ndi makompyuta zambiri masiku ano amalembedwa kusintha muzochitika zones za zochita za anthu. Koma onse mfundo sichikwiya zinyalala zosafunika mu Intaneti, kupangidwa mwa dongosolo Nawonso achichepere, imene zipangizo ndi zosankhidwa, systematized, ndi chifukwa kuti ali zovuta kupeza ndi kugonjera pa processing wotsatira. Pali mitundu zitatu - kuonetsetsa Nawonso achichepere ubale masanjidwe, maukonde.

zitsanzo lofunika

Tikaonanso zikamera wa zinasokoneza makompyuta, ayenera kuti ndondomeko imeneyi inali yovuta kwambiri, izo zimachokera ndi chitukuko cha zida programmable mudziwe processing. N'zosadabwitsa kuti chiwerengero cha zitsanzo panopa ukufika zoposa 50, koma akuluakulu amaonedwa kukhala masanjidwe, ubale ndi maukonde, amene adakali ankagwiritsa ntchito mu ntchito. Kodi iwo akuimilira?

Masanjidwe Nawonso achichepere ali eg mtengo ndipo wapangidwa ndi deta ya magulu pakati muli kulankhulana. Network Nawonso achichepere chitsanzo chitsanzo zovuta. akuphatikizapo akufanana ufumu, ndi chiwembu kukodzedwa ndi bwino. Kusiyana pakati pa iwo ndi kuti cholowa zitsanzo masanjidwe deta akhoza zogwirizana ndi kholo limodzi lokha, pamene maukonde angakhale angapo. Kapangidwe cha ubale Nawonso achichepere ndi zambiri zovuta. Choncho, ayenera ankaiphwasula mwatsatanetsatane.

Cholinga chenicheni cha Nawonso achichepere ubale

chitsanzo ichi anayamba kupanga mu 1970 ndi Dr. Edgar F. Codd sayansi. Ndi tebulo nawatsimikizira kusasintha ndi minda zimafotokoza deta, ubale wawo ndi mzake, ntchito anachita pa iwo, ndipo ambiri Chofunika - malamulo amene amatitsimikizira okhulupirika. Chifukwa chake imatchedwa chitsanzo ubale? Bukuli lili ndi ubale (ku Latin. Relatio) pakati deta. Pali matanthauzo ambiri izi mtundu wa Nawonso achichepere. matebulo Chiyanjano ndi uthenga zosavuta kukonza zoti kupereka chithandizo, m'malo Intaneti kapena chitsanzo masanjidwe. Kodi inu muchita izo? Chakwanira kudziwa zinthu, kapangidwe lachitsanzo katundu wa matebulo ubale.

The ndondomeko ya mawerengeredwe ndi zofunika zinthu

Kuti alenge Nawonso achichepere anu, muyenera kugwiritsa ntchito imodzi ya zida mawerengeredwe kuganiza ndi zimene mukufuna kupeza ntchito, kupanga tebulo ubale ndi maulalo limodzi ndi angapo pakati pa mabungwe deta kudzaza kwa chipinda ndipo anaika mafungulo yaikulu kapena yachilendo.

Kumutsatira matebulo ndi angagwiritse zinasokoneza makompyuta ubale imagwiridwa mwa zida ufulu ngati Workbench, PhpMyAdmin, Mlanduwu situdiyo, dbForge situdiyo. Pambuyo mapulani mwatsatanetsatane kupulumutsa likutipatsa yomalizidwa ubale lachitsanzo kumasulira mu kachidindo SQL-wokonzeka. Pa nthawi imeneyi, mukhoza kuyamba kugwira ntchito ndi deta kusanja, processing ndi systematization.

Features dongosolo ndi mawu kugwirizana ndi chitsanzo ubale

Aliyense kasupe mu njira yake limafotokoza zinthu ake, kotero ine ndikanafuna kuti ndipereke lingaliro pang'ono kuti chisokonezo zochepa:

• ubale chizindikiro = chikhalidwe;
• Kamangidwe = am'patse dzina = gofu = ndime chamutu gulu;
• chilli Mwachitsanzo = tuple = Mbiri = mbale mzere;
• chikhumbo = mtengo = mabungwe selo kumunda.

Kupita ku katundu ubale Nawonso achichepere ayenera kudziwa zina zigawo zikuluzikulu izo limapangidwa ndi umene ukunenedwa.

1. Chofunikira. Table ubale Nawonso achichepere akhoza kukhala mmodzi, kapena kukhala ya matebulo zomwe anafotokoza zinthu kusungidwa m'menemo kudzera deta. Ali ndi chiwerengero atathana minda, ndi variable chiwerengero cha zolemba. Table ubale chitsanzo Nawonso achichepere wapangidwa ndi zingwe, makhalidwe ndi mawonekedwe.
2. Kujambula - ndi variable chiwerengero cha mizere kuti kusonyeza deta zomwe chinthu anafotokoza. Kuwerenga zolemba anapanga makina dongosolo.
3. Zambiri - Data osonyeza SUMMARY mizati.
4. Field. Ndi mudzagwiritse yachiwiri. chiwerengero chawo - phindu lokhazikika amamasulidwa pa chilengedwe kapena kusinthidwa pa tebulo.

Tsopano, podziwa zinthu constituent pa tebulo, mukhoza kupita mu katundu wa ubale chitsanzo Nawonso achichepere:

• Akamanena za ziwiri ooneka enieni ubale Nawonso achichepere. Chifukwa katundu nawo mosavuta prodelyvat zosiyanasiyana zomveka masamu ntchito.
• Dongosolo la makhalidwe khalidwe ndi mbiri mu tebulo ubale kungakhale umasinthasintha.
• Ndime mkati tebulo ubale ayenera yake dzina lapadera.
• deta onse ndime ya kwenikweni ndi kutalika amodzi ndi mtundu womwewo.
• kulowa iliyonse kwenikweni imatengedwa ngati chidutswa chimodzi cha deta.
• zigawo Constituent mizere ndi wapadera. Chikhalidwe ubale palibe mizere chibwereza.

Yachokera pa katundu wa Nawonso achichepere ubale ndi anamvetsa kuti mfundo za makhalidwe akhale amtundu umodzi, kutalika. Taonani makamaka mfundo lingaliro.

Makhalidwe chachikulu cha minda ya zinasokoneza makompyuta ubale

maina Field ayenera kukhala wapadera mu gulu limodzi. Mitundu ya makhalidwe kapena minda ya zinasokoneza makompyuta ubale pofotokoza gulu deta kusungidwa mu minda chilli. Field ubale Nawonso achichepere ayenera kukula amodzi amene masamu zilembo. Magawo ndi mtundu mfundo chikhumbo chimatanthauza unsembe wa kukonza deta awo. Koma pali chinthu chotero monga "chigoba" kapena "athandizira Chinsinsi". Bukuli lakonzedwa kudziwa kasinthidwe wa athandizira deta mtengo khalidwe. Ndithudi pa cholakwika mbiri mtundu deta iyenera chikalata kwa lipoti kachilombo m'munda. Komanso pa munda zinthu ndi zofooka - zinthu poona olondola ndi cholondola cha kulowa deta. Pali kuvomerezedwa khalidwe phindu kuti mwapadera ayenera kudzazidwa ndi deta. Ena mzere chikhumbo kutinso mudzazidwe ndi NULL-mfundo. Sanaloledwe kulowa kanthu munda deta makhalidwe. Mofanana ndi lipoti cholakwika, pali zinthu zina zofunika ndizodzazidwa ndi makina dongosolo - ichi deta ofikira. Mofulumira kufunafuna deta aliyense anafuna munda chakumapeto kwake.

Chiwembu ooneka enieni ubale Nawonso achichepere tebulo

Kumvetsa bwinobwino za kasamalidwe dongosolo chitsanzo ntchito SQL bwino kuganizira chiwembu chitsanzo. Ife tikudziwa kale chiyani Nawonso achichepere ubale. Kulowa aliyense tebulo - ndi deta umodzi amafotokozera. Pofuna kupewa deta redundancy, m'pofunika matenda opaleshoni.

Malamulo yaikulu ya normalization zachilengedwe ubale

1. kufunika kwa dzina la munda kwa tebulo ubale ayenera kukhala lapadera zosowa (Choyamba Normal Fomu - 1NF).

2. tebulo kale kusanduka 1NF, si akudzizindikiritsa dzina la ndime iliyonse kudalira wapadera dzina tebulo (2NF).

3. Pakuti magome onse amene kale kusungidwa mu 2NF, si akudzizindikiritsa aliyense munda angathe muulamuliro wa ena mfundo wosadziwika mchitidwe (3NF chilli).

Zinasokoneza makompyuta: limasonyeza ubale pakati pa matebulo

Pali 2 waukulu mitundu ubale miyala ubale:

• "Chimodzi-ambiri". Malinga kumachitika pamene nthawi ya chifungulo imodzi yokhalira tebulo kulowa №1 angapo a gulu lachiwiri. Zizindikiro zofunikira pa wina wa malekezero a mzere kukopedwa limasonyeza kuti thunthu ndi mbali ya "munthu", mapeto ena a mzere zambiri chizindikiro cha chizindikiro osawerengeka.

• Communication "ambiri-ambiri" kupangidwa mu nkhani ya mizere angapo wina zomveka chilli mogwirizana zolaula angapo za mbiri tebulo lina.
• Ngati mabungwe awiri pali concatenation ya "munthu mmodzi", ndiye kuti dzina chifungulo cha patebulo alipo mu gulu lina, ndiye m'pofunika kuchotsa tebulo lina la mabuku, ndi zosafunika. Koma nthawi zina yekha kwa mapulogalamu chitetezo mwadala kupatukana mabungwe awiri. Choncho, hypothetically, kugwirizana "munthu mmodzi" akhoza kukhalapo.

Kupezeka kwa mafungulo ku Nawonso achichepere ubale

makiyi pulayimale ndi sekondale kuzindikira kuthekera ubale Nawonso achichepere. Chiyanjano deta kulankhulana chitsanzo akhoza kukhala mmodzi yekha phungu kiyi, zidzakhala chinsinsi chachikulu. Ndi chiyani icho? Pulayimale kiyi - mzati kapena ya makhalidwe alili, kupyolera mu zimene mungapeze mwayi makamaka mzere deta. Izo ziyenera kukhala lapadera yekha, ndi madera ake simungakwaneko mfundo null. Ngati chinsinsi chachikulu imakhala mbali imodzi yokha, ndiye anati kukhala wophweka, mwinamwake adzakhala.

Kuwonjezera chinsinsi chachikulu, alipo ndi kunja (kiyi yachilendo). Ambiri sadziwa kusiyana pakati pa iwo. Tiyeni tione iwo mwatsatanetsatane chitsanzo. Choncho, pali matebulo awiri: "Dean" ndi "Ophunzira". Akamanena za "Dean" lili minda: ". Gulu" "ID wophunzira", "Dzina" ndipo Table "Ophunzira" ali ndi lingaliro makhalidwe monga "Dzina", "Gulu" ndi "Avereji". Choncho monga wophunzira ID sangakhale chimodzimodzi kwa ophunzira ochepa, ndi m'munda kukhala ofunika choyambirira. "Dzina" ndi "Gulu" pa "Ophunzira" pa tebulo akhoza kukhala chimodzimodzi kwa anthu ochepa, iwo akusonyeza nambala ID wophunzira kuchokera akamanena za "Dean", kotero iwo angagwiritsidwe ntchito ngati makiyi lachilendo.

Chitsanzo cha chitsanzo ubale Nawonso achichepere

Chifukwa ndi losavuta kumva, timapereka chitsanzo yosavuta ndi ubale chitsanzo Nawonso achichepere wopangidwa mabungwe awiri. Pali tebulo ndi dzina "Dean".

M'pofunika kuchita mogwirizana kuti zonse ubale Nawonso achichepere. Kulowa "MU 41" komanso "MU 72", akhoza kupezeka kangapo pa tebulo "Dean" monga dzina, dzina ndi patronymic wa ophunzirawo, mu nthawi zina, ifenso, kotero m'minda awa akhoza kukhala kuti chinsinsi chachikulu. akamanena za "Ophunzira" adzakusonyezani.

Monga tikuonera, mitundu ya minda ubale Nawonso achichepere amasiyana kotheratu. Pano monga kujambula digito ndi khalidwe. Choncho, zoikamo chikhumbo zisonyeze mtengo wa inteja, gale-, vachar, tsiku ndi ena. Mu "Dean" mtengo wapadera ndi kokha wophunzira ID. Pofunika angathe kumwedwa monga kiyi yoyamba. Dzina, wojambula, ndi foni kuchokera akamanena za "Ophunzira" angathe kumwedwa monga kiyi yachilendo akafuna ndi ID ya wophunzirayo. kugwirizana udzakhazikitsidwe. Ichi ndi chitsanzo cha chitsanzo kulankhulana kwa "munthu mmodzi". Hypothetically, tebulo lina la mabuku owonjezera, iwo mosavuta amaphatikizidwa mu gulu limodzi. Kwa ID-Chiwerengero cha ophunzira sanakhale konsekonse amadziwika zikuoneka kuti pali matebulo awiri.