Ko te mahi matua o te DBMS

Modern pūnaha pātengi raraunga whakamahia i runga i ngā maha, engari e mohio e kore katoa te mea e ratou, ka pehea koe e taea te whakamahi i ngā mahi pātengi raraunga. Enei taputapu Ko te maha nui o taea, na kia matau koutou e taea e ratou me he aha pai mo te kaiwhakamahi ki te whakamahi i tino ratou.

whakahaere raraunga

I roto i te wahi tuatahi, i roto i nga mahi pātengi raraunga ngā te tukatuka o ngā mōhiohio i roto i te mahara o waho, me tenei mahi ko te whakarato o te hanganga taketake o te EP, e kua hiahiatia ki ngā mōhiohio taonga tika ngā i roto i te pātengi raraunga e kore anake, engari ano ki te mahi i ngā mahi tari, pērā i te whiwhi nohopuku whai wāhi ki tetahi kōnae i runga i ngā wā rerekē. I roto i etahi taatou, mātātoa whakamahia te taea o ngā pūnaha kōnae rerekē, ētahi atu i te whakarato mō te mahi, ara i te taumata o ngā pūrere mahara waho. Otiia i roto i tenei take ko reira ia tapao e te mahi pātengi raraunga, me te nui rawa o te whanaketanga, te kaiwhakamahi, i roto i tetahi take, ko te kore mōhio o ahakoa whakamahia tetahi pūnaha te, a ki te pera, me pehea ki te whakarite i ngā kōnae. I roto i ngā, kua te pūnaha kua tautoko i ona ake tikanga whakaingoa i te taonga ngā i roto i te pātengi raraunga.

whakahaere moka RAM

I roto i te nuinga rawa o te wā he noa te mahi pātengi raraunga ki te whakamahi i te pātengi raraunga tika whakaemi me te rahi iti rawa, ko te maha noa ake e wātea ana RAM. O te akoranga, ki te i roto i te take o te maimoatanga mō ia tūemi raraunga ka kia whakawhiti ki te mahara waho, ka ōrite te tere o te muri te tere o te pūnaha, kia tata te kōwhiringa tūturu anake, ko te ki te whakapiki ake i ona raraunga pūreirei i RAM. I roto i tenei take, ara, ki te whakarato i te pūnaha whakahaere i te moka pūnaha-whānui, hei tauira ki UNIX, e kore te tenei e kia nui ki te whakarite kia te pātengi raraunga i roto i nga mahi whakaaro me matua, ka rite ki te mea he rōrahi nui nui o ngā raraunga i runga i te āhuatanga painga o pūreirei ia wahi motuhake o te pātengi raraunga e whakamahia. Nā ki tenei pūnaha whanaketanga ki te tautoko i tona huinga ake o ngā moka, me te he ako ahurei ratou whakakapinga.

E tano ia tapao i te meka i reira ko te raina motuhake o ngā pūnaha whakahaere, e arotahi ana ki te aroaro tonu i roto i te mahara o te pātengi raraunga katoa. hāngai ana tēnei aronga i runga i te whakaaro e roto i te heke mai tata ka taea ki te whakawhānui pera kore e e kia o tetahi āwangawanga pūreirei, a ka hinga nga mahi taketake o tenei momo o te pātengi raraunga i konei tika i roto i te wa i te nui o te RAM i runga i tō rorohiko. I te kau, he tonu enei mahi katoa i roto i te wāhanga whakamātautau.

whakahaere tauwhitinga

He hoko ko he raupapa o ngā mahi ki te whakamahi o te pūnaha whakahaere turanga raraunga e tiaki rite te hinonga kotahi. Ki te te tino mahi i pai te hoko, kapo te pūnaha kore e e kitea nga huringa e kua hanga e reira, i roto i te mahara waho tetahi o enei huringa ranei i runga i te āhua o te pātengi raraunga. hiahiatia ana tēnei mahi i roto i te tikanga ki te tautoko i te tapatahi arorau o te pātengi raraunga e whakamahia. Me kï reira e te tiaki o te akoranga tika o te huarahi hoko ko he titauraa noa ka whakamahi i te pātengi raraunga kotahi-kaiwhakamahi, te whakaaro me te mahi e tino rerekē i ētahi atu momo o ngā pūnaha o nei.

Ko te taonga e haamata noa tetahi hoko i te āhua ōrite pātengi raraunga , me te kupu rau te reira i roto i te āhua taua i muri i te mutunga o te tikanga, hanga i te reira tino watea ki te whakamahi i rite te kōwae o te mahi i runga i te pātengi raraunga. Ki te e mahi ana te whakahaere tika o whakawhitinga i roto i te whakarara i te pūnaha mana o ia kaiwhakamahi takitahi, i roto i te parau tumu, e taea ite wahi o te katoa. Heoi, ko tenei i roto i te tahi mau ara i te kanohi Päkehä, pera i roto i ngā āhuatanga maha, ka tonu e ite iwi mahi i te aroaro o tona hoa, ki te whakamahia e ratou he pūnaha multiuser, engari i roto i te meka whakarato reira te ariā rawa o te pātengi raraunga. Mahi pērā i pātengi maha-kaiwhakamahi kua hoki i pā ana ki te ariā whakahaere tauwhitinga pērā i te mahere mahi rangatū, me serialization.

He aha te tikanga ratou?

Serializing tauwhitinga whakamahi whakarara tā te hanga motuhake o ratou mahere mahi, ai te mea ōrite ki te ranunga hua whiwhi te katoa pānga tutuki, no te mea o ratou mahi raupapa.

Ko te mahere mahi Serial te hanganga motuhake o te mahi, e tika ana ki te serialization. O te akoranga, ki te whiwhi te pūnaha te ki te whakarato i tētahi He pono mahi rangatū o whakawhitinga ranunga, ka tetahi kaiwhakamahi e hangaia te hoko, ka kia tino äta te aroaro o etahi atu, ki te kahore e ka mahi i te reira i te moka pōturi whakaritea ki te aratau kotahi-kaiwhakamahi.

He etahi hātepe serialization taketake. I roto i ngā pūnaha centralized, te tino rongonui tenei ra ko nga hātepe e kua hāngai i runga i nga taonga pātengi raraunga rerekē tukutahitanga hopu. I roto i te take o tetahi hātepe papatono serialization whakarato mo te taea o te pakanga i waenganui i rua, neke atu rānei ngā whakawhitinga i runga i te whai wāhi ki etahi ahanoa pātengi raraunga. I roto i te āhuatanga i taua, ki te tautoko i tenei tikanga, e hiahia ana koe ki te hurihia hoki, e ko, ki te whakakore i tetahi huringa i hanga ki te pātengi raraunga i roto i tetahi atu ranei tukanga. Ko te tika tenei tetahi o nga mau huru i reira te pūnaha maha-kaiwhakamahi, mana'o tetahi te aroaro o ētahi atu.

te takiuru

Ko tētahi o nga whakaritenga matua mō ngā pūnaha hou ko ki te whakarite i te tika o te mōhiohio rokiroki i roto i te mahara waho. I roto i ngā, whakarato reira e ngā tetahi o nga mahi matua o te pātengi raraunga te kaha ki te whakahoki mai i te āhua mārama whakamutunga o te pātengi raraunga i muri i te takanga o tetahi kore pūmanawa pūmārō ranei. I roto i te nuinga rawa o ngā take i tangohia ki te whakaaro e rua ngā kōwhiringa mō ngā rahunga pūmārō:

• ngohengohe, e taea te whakaatu ai rite te mutu ohorere o tō rorohiko (te take tino noa - Emergency Power Off);
• mārō, e kua āhuatanga e mate wāhanga oti ranei o raraunga rongoa i runga i pāpāho waho.

Ka rite ki rahunga pūmanawa tauira whawhati tata whakaweto pūnaha ina ngana ana ki te whakamahi i tetahi taea e tetahi o nga mahi matua o te DBMS kore e whakaurua ranei e tutuki tetahi whaipainga kaiwhakamahi, ai kore kua oti tetahi tauwhitinga. kia whakaaro te āhuatanga tuatahi rite te ahua motuhake o te kore ngohengohe, i roto i te take o te muri, ko te tika ki te whakakore i te mau hopearaa o te tauwhitinga kotahi.

O te akoranga, i roto i tetahi take mo te whakaora pātengi raraunga noa he tika ki te whai i te nui etahi o te mōhiohio atu. I roto i te mau parau te tahi atu, mo te tiaki noa o te tika o te rokiroki raraunga i roto i te pātengi raraunga me whakarite e koe te hapanga o ngā mōhiohio rokiroki, me te wahi o te raraunga whakamahia i roto i te whakaora kia tiakina āta. Ko te tikanga nui rawa mō o te whakarite i te tiaki o ngā raraunga i näianei, kua whakaaro ki te kia te takiuru huringa.

He aha te mea te reira, ka pehea ki te whakamahi i?

Ko te moheni ko te wahi motuhake o te pātengi raraunga, uru nei i roto i kore e he maha o ngā mahi pātengi raraunga ngā, me te rawa āta tonu reira. I roto i te tahi mau āhuatanga, ara i te wa ano whakarato reira tautoko mō te rua ngā tārua o te makasini, i pāpāho tinana rerekē. I roto i te toa i whiwhi mōhiohio e pā ana ki tetahi huringa e puta i roto i te wahi matua o te pātengi raraunga, a kia journaled rerekē ngā pūnaha mana huringa i ngā taumata rerekē. I roto i te tahi mau āhuatanga, he tino hāngai ki te ngā i te urunga roko mahi arorau huringa, vahi - he mahi ā-iti e pā ana ki te whakarerekē whārangi mahara waho, i te tahi mau DBMSs whai wāhi te whakamahi i te huinga o rua huarahi.

I roto i tetahi take, he pera-ka karanga "rautaki o te tuhi i mua i-kāwanatanga" i roto i te moheni. I roto i tona record tono, tohu he huringa i roto i tetahi ahanoa pātengi raraunga taka ki te mahara waho o te makasiní te aroaro o te ahanoa tāupe. Kei te mohiotia te reira e te mea te mahi pātengi raraunga Access ngā te tautukunga noa ki tenei kawa, te whakamahi i te moheni ki te whakaoti i tetahi raruraru e pā ana ki te whakaora pātengi raraunga i roto i te hui o tetahi rahunga.

utu te

Ko te āhuatanga māmā ko hurihia te te faaho'iraa mai o te hoko takitahi hoki. Hoki tenei tukanga, e kore te mea e tika ana ki te whakamahi i te huringa roko pūnaha-whānui, me he reira nui ki te whakamahi hoki ia tauwhitinga he ngā mahi makasini whakarereke rohe, a ka hurihia hoki te hoko i mahi i te ngā mahi kōaro, timata mai i te mutunga o ia record. maha Ko tā te hanganga o te mahi pātengi raraunga te whakamahi o te hanganga taua tika, engari i roto i te nuinga o te wā e kore e tonu te rangitaki rohe tautoko, me huriwhakamuri ara takitahi o whakawhitinga takitahi kawea atu e te pūnaha-whānui, me mo e ngā pūkete katoa o ia tauwhitinga ngā rārangi whakamuri.

I roto i te hui o te mahara pātengi raraunga o waho kore ngohengohe taea ngā ngā ahanoa e kua whakarerekētia e te whakawhitinga kore oti e te wa o te tupu o te kore, a hoki kia kore taonga rerekē, hunga ake i pai i oti i mua i te hara ki te taha o te whakamahi i te tirotiro RAM moka e tino riro i te reira e raruraru ōrite. Ki te haapa'o te kawa te ki, te whakarato hoki i te whakamahi o hautaka rohe e tika tuhituhi i roto i te mahara waho, e hāngai ana ki akatuke'anga o tetahi taonga pera.

Ko te whakaaro matua o te tukanga ora i muri i te takanga o te kore ngohengohe ko te āhua o te mahara waho o te pātengi raraunga matua, e pai ara ake i roto i te take o whakatika i roto i te EAP tetahi huringa mō oti tauwhitinga me te kupu kihai i pai i roto i tohu o ngā tukanga oti. Hei whakatutuki i tenei pānga, te mahi pātengi raraunga nui kei roto i tenei take, huriwhakamuri whakawhitinga kia here, faahiti i te mahi, te hua o nei e kore te mutunga e puta i roto i te mahara waho. Tenei tukanga tā te rota tonu o whaktauiratia, e te nuinga pā ki te whakahaere o te whakahaere o te makasiní me monoprotic.

rahunga Hard

Ki te tika, whakahokia te pātengi raraunga i muri i te takanga o rahunga pakeke ko te moheni kore anake, engari ano hoki i te tārua pātengi raraunga. Ko te whakamutunga, ko te he kape oti o te pātengi raraunga i taua wa rite te moheni timata ki te whakaki. O te akoranga, mo te tukanga whakaora noa titau te haumaru makasini, reira, rite whakahuatia mua, ki tona tiaki i roto i te mahara waho utaina whakaritenga rawa tino. I roto i tenei take, whakaora o te pātengi raraunga, ko e, e hāngai ana i runga i nga kape pūranga o te moheni e takaro whakawhitinga whakahaere katoa oti i te wa o te kino. Ki te tika, ara e taea te takaro reira mahi whakawhitinga kāore me tonu ratou mahi noa i muri i te mutunga o te tukanga whakaora, engari i roto i te nuinga o ngā pūnaha tūturu, e kore te he tukanga taua kawea atu mo te take e i roto iho ora i muri i te kore pakeke ko te tukanga āhua roa.

Tautoko reo

Ki te mahi ki te pātengi raraunga hou whakamahi reo rerekē, me i roto i te tīmatanga o pātengi raraunga, whakarite, mahi, me te tahi atu āhuatanga e he tino rerekē i te pūnaha hou whakarato tautoko motuhake mō ngā reo maha. Enei i te nuinga SDL ko DML, tikanga ki te tautuhi i te aronuinga pātengi raraunga me raraunga whawhe, aua.

whakamahia SDL te ki te tautuhi i te hanganga arorau o te pātengi raraunga, e ko, ki te ite i te hanganga motuhake o te pātengi raraunga, e te mea e wātea ana ki ngā kaiwhakamahi. DML hoki ngā te huinga o ngā whawhe o ngā mōhiohio, ka taea ki te rokiroki koe ngā mōhiohio i roto i te pātengi raraunga, me te muku, whakarerekē ranei te whakamahi i te raraunga tīariari.

DBMS āhuatanga ngā momo rerekē o te tautoko te reo integrated kotahi e whakarato mō ngā rauemi katoa e hiahiatia ana mō te mahi noa o pātengi raraunga, i tona hanganga tuatahi, a ka whakarato he atanga kaiwhakamahi paerewa. Ko te reo paerewa e whakarato ana i te mahi taketake o te pātengi raraunga te noa tino i roto i to tatou ra o pūnaha tūhonohono, whakamahia e te SQL.

He aha te mea te reira?

I roto i te wahi tuatahi fakatahai te reo te mahi taketake o DML ko SDL, e ko, whakarato te taea o te whakatau i nga semantics motuhake o te pātengi raraunga tūhonohono , ka rāwekeweke i te kōrero e tika ana. Ko te kupu rerekē ahanoa whakaingoa pātengi raraunga tautoko tika i runga i te taumata reo i roto i te tikanga i kawea i te faafariuraa i roto i te taha o te ingoa ahanoa taupatupatu i roto i o ratou pūwehe ā, e hāngai ana i runga i nga papa ratonga tautoko rawa-whaiaronga. Ko te matua o te pūnaha mana, i roto i te parau tumu, e kore e taunekeneke ki tepu tīwae takitahi ranei.

Kei roto te reo SQL he rārangi o ngā taputapu motuhake ki te tautuhi i herenga pātengi raraunga. Ano, kei te ngā i tetahi here pera i roto i te papa motuhake, putumōhio, ka kawea aroturuki tapatahi i roto i tika i runga i te taumata reo, e ko i te tukanga o te tai'oraa i tauākī pātengi raraunga whakarereke takitahi taupatupatu, e hāngai ana i runga i te wātea i roto i te herenga tapatahi pātengi raraunga, noho ki te whakaputa i te waehere hāngai.