Ukuthenga - ntoni na? Le database transaction

A Okwenziwayo uthotho lokwenzekayo ethile eyenziwa ngumntu okanye inkqubo ukungena okanye aguqule kancinane i ledatha. Phambi kokuba deal, intengiselwano - ukuba kuyimfuneko ukuqonda kakuhle le nkqubo. Intsingiselo esisiseko inkqubo amanga neqiniso ukuba isenzo kufuneka nokuba ngokupheleleyo okanye irhoxisiwe.

yokwenzekayo database ngalinye kufuneka ndiyiguqulele ukusuka kwimo enye, nto leyo efanayo enye. Kuthathwa ukuba guquki ukuze iyolala kule nkqubo.

Abantu abaninzi uyazibuza, intengiselwano - yintoni na. Le yunithi umsebenzi kwenziwa kwiziko ledatha. Kunokuba ibe yinxalenye algorithm ngokubanzi, iqela eyahlukileyo okanye inkqubo xa iyonke.

Intengiselwano kufuneka izaliswe?

Kukho iindlela ezimbini zokuyigqiba:

• Kwimeko apho intengiselwano yagqitywa ngempumelelo, iziphumo zibhalwe, kwaye database ingena urhulumente kuhambelana omtsha (benze).
• Ukuba abulawe waya, wajika impazamo intengiselwano engalunganga, kokuba irhoxisiwe. Kulo mzekelo weenkcukacha kufuneka zibuyiselwe kurhulumente ekuqaleni. Le meko ibizwa ngokuba "ukubuyisela ngemva" (ukubuyisela ngemva). Noko ke, ukuba intengiselwano iye yabhalwa, mayingabi sakhululwa irhoxisiwe. Ukuba intshukumo kwafunyaniswa ukuba ayichanekanga, kuyimfuneko ukwenza enye intengiselwano eza kubuyela ledatha ukuya kwimo engaguqukiyo.

iimpawu yentengiselwano

Ukuphawula umda intengiselwano samkelwe ukusebenzisa abaqhubi ukuqala izivumelwano, enze, ukubuyisela ngemva.

Acid, okanye iimpawu intengiselwano kuba ngolu hlobo lulandelayo:

• Atomic, okanye atomicity. Ngento - unit ayahlukahlukenanga, ekufuneka mhlawumbi babulawa okanye irhoxisiwe.
• Uququzelelo, okanye ukuzinza. Intsingiselo intengiselwano kukuba database esuka kwimo enye efanayo komnye.
• Insulativity, okanye yodwa. ukuthenga ngalinye ikhutshwa phandle, akuxhomekekanga kwabanye. Zonke iziphumo zenkqubo ziyafumaneka kwi izithuba akufuneki zuku bonakala kwabanye imicimbi.
• Ubude, okanye ixesha. Zonke iziphumo ezifunyenweyo ngexesha intengiselwano ngempumelelo akufunekanga yalahleka iintsilelo ezilandelayo. Bona abagcinwe database ngokusisigxina.

Intengiselwano zisetyenziselwa ukwenza utshintsho okanye nogqibo ledatha. inkqubo nganye kulawulwa ize ilawulwe ngumphathi intengiselwano kunye resource - nomphathi resource. Intsebenziswano ye nabaqondisi ababini kugqiba kwisiphumo msebenzi. Iintengiselwano wenziwe lock xa kuyimfuneko.

isigaba transaction

Kukho ezi zigaba zilandelayo:

• Active. Kwesi sigaba intengiselwano wadala kwinkqubo Abaphathi bobutyebi inxaxheba.
• Preparatory. Ngeli xesha, umphathi resource ngamnye uyakwazi lokugqiba ngesiphumo lo msebenzi. Ukuqala isigaba kwenzeka xa umqalisi yenza isicelo ukugqibezela bethenga. Ukuba umphathi resource akanalo nexesha elaneleyo, kudinga dispatcher ukuthumela ukubuyisela intengiselwano. Abaphathi Resource ukuba iijenali ukuba babhale yonke i data kwi zikulungele. Oku kwenzelwa ukuqinisekisa ukuba xa kuthe ezinxaxhileyo waba ithuba lokuqhubeka ukusebenza kwindawo ethile.
• Nitrogen. Ukuqala yesi sigaba mzuzu xa bonke abaphathi resource ukulungele ukusebenza. Ukuba kuyimfuneko, eli dispatcher intengiselwano siyakwazi ukubona ukusebenza.

zentengiselwano nganye kufuneka kuxhomekeke kwiimfuno ezithile. Ngenxa yenkqubo msebenzi kufuneka bangeniswe ngurhulumente echanekileyo. Le meko kuyimfuneko kwimeko apho kukho ukusilela kwi umbane.

imbawula transaction

Ngexesha lo msebenzi wenziwe neloge izivumelwano, apho zibhalwe zonke utshintsho. Kuyimfuneko ukuba libe rhoqo, ngomlinganiselo kuya kukunceda ukuba uphephe ukuphuphuma. Nangona kunjalo, kukho eziliqela izizathu zokuba kutheni akhronimi nga fiki ngeli thuba kubaluleke ngokukhethekileyo esweni umxholo. Ukunciphisa ubungakanani log, unako ukwenza imisebenzi kancinane ngemvume.

Kwimeko ye log ukungaphumeleli yinxalenye ebaluleke kakhulu umsebenzi eziya kunceda ukuba kuvimba ukuya kwimo engaguqukiyo. Le magazini kufuneka lingatshitshi okanye zisuswe.

Iingenelo usebenzisa log transaction

Oku kwenza kube lula ukuba ukuxhasa imisebenzi enjalo:

• ukubuyisela ngabanye;
• kwakhona iintlawulo azizange zigqitywe;
• enze uluhlu intshukumo phambili ukungaphumeleli;
• ukwenza ukuphindaphindeka yentengiselwano.

Njani na akhronimi ye log?

Xa inkqubo truncating ekhululwe kwifayile, esetyenziswa orekhodiweyo phambili. Ukuba sityeshele le nkqubo, zonke isithuba kwidiski abahlala kuwo, yaye apho kuya kubakho iingxaki ezininzi. Ukuze siphephe imeko enjalo, akhronimi kwenzeka ngokuzenzekelayo, ngaphandle xa isalityaziswa ngenxa yezizathu ezizimeleyo.

Intengiselwano ngekhadi credit

Yenza intlawulo ngokusebenzisa yeevenkile yentlawulo, abathengi abacinga: isivumelwano - yintoni na yaye yintoni na ke ngenxa? iintengiselwano ezinjalo nge-credit card njengoko zokurhoxa yemali, recharge akhawunti, okanye ukwenza transfers, ebizwa kwentengiselwano. Le mbono esetyenziswa ekubaleni ikhadi yentlawulo a kwakunye neevenkile.

Ukwenza intlawulo nge-credit card, asizizo zonke umxhasi ucinga ngento iinkqubo kwenzeka ngeli xesha. Nangona olu lwazi kubaluleke kakhulu, kuba sithetha ngayo imali kunye nokhuseleko.

Ngoko ke, lo intengiselwano - yintoni kubalo le venkile? Lo msebenzi iqulathe amanyathelo eziliqela, ezithi ezihambelanayo.

Abathathi-ephambili kwinkqubo - yinto ebhankini (umkhuphi-) ekhuphe ikhadi intlawulo, kwaye ebhankini (uyinikezelwayo), ezithengisa nkonzo. Kakuhle eli ukusebenza amanga neqiniso yokuba uyinikezelwayo ufuna ukufumana ukusuka imvume kwi Umnikeli ukuba baqhube zoshishino. Esebenzisa ikhadi nge-terminal, uthumela asongiweyo isicelo osethilini kunye iinkcukacha eziyimfuneko ukulungiselela umsebenzi. Zonke iinkcukacha eziqulathwe komcu ngemagnethi.

Esi sicelo luthunyelwe kwiziko processing, apho msebenzi processing kunye yokusiwa kwee kolwazi ebhankini elikhupha. It ihlaziya ulwazi ulifanisa kunye data. Ukuba kuvela naziphi na ingxabano, umnikeli liya kukhupha imvume ukwenza itransekshini. Kakuhle eli nkqubo ukuba zinyule ikhowudi yogunyaziso lobuqu.

Kuphela emva uyinikezelwayo ukuze enze lo msebenzi, nto leyo ekhokelele imali isuke kwi-akhawunti yoMthengi kumaKanan. Kwimeko yokusilela isixhobo uya kukuxelela ukuba akakwazi kuyizalisa lungamkeleki.

Loo itransekshini database kwenziwa ngekhompyutha. Kukho olunye uhlobo zentengiselwano, offline, leyo ziveliswa ngendlela imprinter ukwenza ikhadi yamanyala.

Abantu abaninzi banomdla: nokuba kunokwenzeka ukuba umva lungamkeleki? Ukuba kuyimfuneko ibhanki linokuyiqhuba zazo ezithile ukuvumela ukwenza njalo.