Yikuphi ngempela i-UUID
I-UUID, esifushaniswa kusuka ku-Universally Unique Identifier, iyivelu ye-128-bit esetshenziselwa ukuphawula into ngaphandle kokucela imvume kuqala. Ungabuye uyibone ibizwa nge-GUID, noma i-Globally Unique Identifier, okuyilona nje igama i-Microsoft eyalinika lo mqondo ofanayo ngaphakathi kwe-Windows nomhlaba we-.NET. Amagama womabili achaza inombolo efanayo ye-128-bit cishe kuzo zonke izimo ezibalulekile, ngakho lapho ozakwenu ethi GUID kanti wena uthi UUID, cishe njalo nikhuluma ngento efanayo ngokuphelele.
Lawo ma-bit angu-128 avame ukubhalwa njengezinhlamvu ze-hexadecimal ezingu-32 ezihlukaniswe ngamaqembu ayisihlanu ngophawu lokuxhumanisa, ngephethini ye-8-4-4-12. Ivelu evamile ibonakala kanjena 123e4567-e89b-12d3-a456-426614174000. Uphawu lokuxhumanisa aluthwali muqondo ngokwalo; ludalelwe nje ukuthi umuntu akwazi ukufunda ivelu ngaphandle kokulahleka. Uhlamvu ngalunye luyinhlamvu ye-hex kusuka ku-0 kuya ku-f, yingakho i-UUID izwakala isinda kunenombolo yansuku zonke nakuba, ngaphansi kwesibonelelo, iyinombolo eyodwa enkulu kakhulu.
Izinhlobo, nokuthi kungani u-v4 enqoba
Isimo sichaza izinhlobo eziningana, futhi zihlukene ngendlela ama-bit agcwaliswa ngayo. Uhlobo 1 lususelwa esikhathini: lihlanganisa isikhathi samanje kanye nekheli le-MAC lenethiwekhi yomshini. Lokho kwenza amavelu e-v1 ahleleka ngesikhathi sokudalwa, kodwa futhi avuza ulwazi mayelana nokuthi adalwe kuphi nangesiphi isikhathi ngokungathi sina, okungahlali kwamukelekile. Izinhlobo 3 no-5 zisuselwa egameni, zi-hash isikhala segama kanye negama ukuze okufakiwe okufanayo kuhlale kudala isazisi esifanayo.
Uhlobo 4 luthatha indlela ehluke ngokuphelele. Cishe lungahleliki nya. Kuma-bit angu-128, ayisithupha agodlelwe ukumaka uhlobo kanye ne-variant, kushiya ama-bit angu-122 ukuthi agcwaliswe ngedatha engahleliki. Akukho isikhathi, akukho ikheli le-MAC, akukho isikhala segama, kuwumsindo nje. Yileso ngempela isizathu izikhiqizi eziningi, kufaka phakathi lena, zikhiqiza u-v4 njengokuzenzakalelayo. Ayiveli lutho ngedivayisi noma umzuzu wokudalwa, futhi ayidingi ukuhlanganyela phakathi kwabahlangana bekwenza. Ithuluzi kuleli khasi lisebenza ngokuphelele ku-browser yakho, ngakho amavelu angahleliki awasoze aphuma emshini wakho.
Ukungenzeki kwangempela kokugxumana
Ukukhathazeka okunengqondo ukuthi ama-UUID amabili angahleliki angahle ngelinye ilanga afane. Nge-122 ama-bit angahleliki, isikhala samavelu e-v4 angaba khona i-2 kwikhono le-122, okuyicishe u-5.3 elandelwa ama-0 angu-36. Ukuyibeka ngendlela umuntu ayizwayo, kufanele ukhiqize izigidigidi ze-UUID isekhondi ngasekhondi iminyaka eminingi ngaphambi kokuthi amathuba wokugxumana okukodwa akhuphuke afinyelele okungalinganiswa. Isimo ngokwaso sichaza ithuba lokugxumana njengeliseduze nezero ngokwanele ukuthi lingabalulekile. Ekusebenzeni amaqembu aphatha u-v4 njengongahleliki futhi aqhubeke, futhi alungile.
Lapho othuthukisi bezinhlelo bezisebenzisa khona
Ngoba ukungahleliki akudingi igunya eliphakathi, ama-UUID akhanya kahle ezindaweni lapho ukuhlanganyela kubiza kakhulu noma kungenzeki. Ahambisana kahle nezihluthulelo eziyinhloko zezizinda zedatha, ikakhulukazi lapho amasevisi amaningana ngayinye ifaka imigqa futhi ungakwazi ukuma ucele isibali esabelwana ngaso inombolo elandelayo. Emasistimini asakazekile, amanodi amabili emaceleni aphambene omhlaba angakwazi womabili ukudala izazisi ngesikhathi esifanayo ngaphandle kokugxumana. Aphinde asebenzise amakhiye e-API idempotency, lapho iklayenti linamathisela i-UUID kwisicelo ukuze iseva ikwazi ngokuphephile ukungakunaki ukuphindwa uma inethiwekhi izama futhi. Amathokheni wesikhathi somsebenzisi, amagama amafayela, izazisi zesehlakalo, kanye nezihluthulelo zomlayezo konke kuthembela kuleyo mpahla efanayo.
I-UUID uma iqhathaniswa nezinombolo ezinyuka zodwa
Enye eyaziwa yinombolo enyuka yodwa: 1, 2, 3, njalo njalo. Izazisi ezilandelanayo zincane, zihleleka ngokwemvelo, futhi zilula ukuzifunda, kodwa zinezinkinga zangempela. Ziveza ukuthi zingaki izinhlaka ezikhona futhi zivumela abangaphandle ukuqagela amavelu aseduze, futhi ziphoqa ukufakwa ngakunye kudlule kusibali esisodwa, okuba yisithiyo lapho uhlukanisa isizinda sedatha noma uhlanganisa idatha evela emithonjeni eminingi. Ama-UUID axazulula lezo zinkinga ngokuvumela noma yisiphi isihlangu ukukhiqiza isihluthulelo ngokuzimela nangokungaveli lutho ngobuningi noma i-oda. Ukuqhathaniswa ubukhulu nokungabi khona okuncane kokwendawo kuma-indeksi. Kumasistimu akhula ngaphandle noma okufanele afihle okungaphakathi kwawo, lokho kuqhathaniswa kuvame ukuba yikhona kufanele kwenziwe. Ungahlola lokhu namanye amathuluzi afanayo ngokusebenzisa iqoqo lethu le-zonke izikhiqizi, noma uphenye isiqoqo esibanzi sama-thuluzi zabathuthukisi ezakhi ezihlobene.
Imibuzo evame ukubuzwa
Ingabe i-GUID ifana ne-UUID?
Ngezinjongo zansuku zonke, yebo. I-GUID yigama le-Microsoft lesazisi esifanayo se-128-bit. Umehluko wangempela kuphela ukuhlelwa kwe-byte ohlelweni lwe-binary olungahlobene kwamanye amasistimu e-Windows; ohlwini lombhalo ziyafana futhi ziyashintshaniswa.
Yiluphi uhlobo lwe-UUID lelithuluzi elikhiqizayo?
Likhiqiza uhlobo 4, i-variant engahleliki. Kuma-bit alo angu-128, angu-122 agcwaliswe ngedatha engahleliki, okwenza ivelu ngayinye kube ngenzeki ngempela ukuphindeka futhi kusho ukuthi akuthwali sikhathi noma ulwazi lwedivayisi.
Ingabe ama-UUID amabili angake afane?
Ngokombono ithuba alilingani nezero ngempela, kodwa ngamavelu e-v4 angaba khona angu-5.3 ephindwe ka-10 kwikhono le-36, lincane kangangokuthi liphathwa njengelingabalulekile. Ubuzokhiqiza izinombolo eziningi kakhulu zawo ngaphambi kokuthi ukugxumana kube nokwenzeka.
Kungani usebenzisa i-UUID esikhundleni senombolo enyuka yodwa?
Ama-UUID angadalwa ngokuzimela yisiphi isevisi ngaphandle kwesibali esabelwana ngaso, awaveli ubuningi bezinhlaka noma i-oda, futhi enza ukuhlanganiswa kwedatha evela emithonjeni eminingi kube lula. Izazisi ezinyuka zodwa zincane kodwa ziba yisithiyo futhi zivuza ulwazi lapho sekukhulile.
Ingabe ama-UUID akhiqizwa kuseva?
Cha. Leli thuluzi lisebenza ngokuphelele ku-browser yakho, ngakho amavelu angahleliki akhiqizwa endaweni futhi awasoze athunyelwa noma yikuphi. Lokho kwenza kuphephe ukusetshenziswa ezihluthulelweni namathokheni ohlose ukuwagcina eyimfihlo.
Kusho ukuthini iphethini yophawu lokuxhumanisa?
Ukuhlukaniswa kwe-8-4-4-4-12 yinqubomgomo yokufundeka nje. Uphawu lokuxhumanisa aluthwali datha; luhlukanisa izinhlamvu ze-hex ezingu-32 zibe yizingcezu ukuze abantu bakwazi ukubheka nokuqhathanisa amavelu kalula.