SQL

I-Oracle Application Express, evame ukwaziwa nge-Oracle APEX, isizuze ukuduma okukhulu phakathi konjiniyela ngokusebenza kwayo okuphezulu kanye nesixhumi esibonakalayo esisebenziseka kalula. Ithuluzi eliqinile lisiza ekwakheni izinhlelo zokusebenza zewebhu eziyinkimbinkimbi ezisekelwa isizindalwazi se-Oracle. Ngaphezu kwalokho, iyindawo enekhodi ephansi, evumela onjiniyela abanolwazi oluncane ukuthi bakhe izinhlelo zokusebenza.

I-Oracle APEX inikeza izinguqulo ezihlukahlukene, ngayinye iletha izici ezithuthukisiwe namathuluzi enqubo yokuthuthukiswa eyenziwe lula nephumelelayo. Ukuvela okuhamba ngokushesha kwe-Oracle APEX kungakwenza kube inselele ukulandelela umehluko phakathi kwalezi zinguqulo.

Uma kubhekwa ubunzima kanye nokuvela okuqhubekayo kwe-Oracle APEX, kubaluleka ukuqonda ukusebenza kwezinguqulo zayo ezihlukile. Ngokuvamile, onjiniyela bangase bafune ukubuza inguqulo ye-Oracle APEX esetshenziselwa ukulungisa ukusebenza, ukusebenzisa amapeshi, noma ukuxazulula inkinga.

Funda kabanzi

Ukudala ukulandelana kuyisici esibalulekile se-Oracle SQL. Ukulandelana kuyizinto zesizindalwazi lapho abasebenzisi abaningi bengenza khona izinombolo ezihlukile. Kungenzeka ukuchaza izici ezithile ezifana nenani lokuqala ongaqala ngalo, usayizi wokukhuphuka, kanye nomkhawulo omkhulu, phakathi kokunye. Izinombolo ezikhiqizwa ukulandelana zingasetshenziselwa izinjongo ezimbalwa ezifana nokukhiqiza izihlonzi ezihlukile, okhiye abayinhloko, izinombolo zokulawula, nokunye okuningi.

Funda kabanzi

Lapho usebenza nezizindalwazi, umsebenzi ojwayelekile ukukhohlisa nokuhlaziya idatha ukuze uthole imininingwane ewusizo. Izikhathi eziningi, lokhu kuhilela ukubhekana nezintambo, ikakhulukazi ukuzihlukanisa ngokusekelwe kuma-delimiter athile. Ku-Oracle SQL, kunezindlela ezihlukahlukene zokufeza lokhu ngokusebenzisa imisebenzi ehlukene namakhodi enqubo. Kulesi sihloko, sizofaka isisombululo esibanzi sokuhlukanisa iyunithi yezinhlamvu usebenzisa i-Oracle SQL. Sizoxoxa ngomqondo, isisombululo, futhi sihlukanise ikhodi ngesinyathelo ngesinyathelo ukuze siqonde kangcono.

Funda kabanzi

I-Drop Rule Set ingumqondo oyisisekelo ku-Oracle SQL, osetshenziselwa ukukhohlisa, ukuphatha, nokuhlela amasethi edatha ngaphakathi kwendawo egciniwe. Isiza ekugcineni ubuqotho besakhiwo solwazi lwesizindalwazi ngokuchaza imithetho ethile ebeka ukuthi idatha ingangeniswa kanjani, ithekeliswe, noma isuswe kanjani. Kulesi sihloko, sizocubungula ukubaluleka kwe-Drop Rule Set, ukulandelana kwezenzo ezidingekayo ukuze kusetshenziswe, kanye nekhodi ethile evumela lokho.

Ku-Oracle SQL, Yehlisa Isethi Yomthetho kuyindlela esetshenziswa ukususa umthetho osethiwe kusizindalwazi. Kusebenza kuzo zombili izakhiwo zedatha ezilula neziyinkimbinkimbi, okwenza ukukhohlisa kwedathabheyisi kube lula ukulawuleka. Ithuthukisa ukusebenza kwesizindalwazi ngokususa amasethi emithetho angadingekile noma aphelelwe yisikhathi kanye nokuthuthukisa ukuphathwa kwedatha.

YEHLISA UMTHETHO SET rule_set_name;

Lena i-syntax eyisisekelo ye-Drop Rule Set. I-rule_set_name yigama lomthetho ofisa ukuwuyeka.

Isinyathelo ngesinyathelo ikhodi incazelo

Ukwenza umsebenzi we-Drop Rule Set kulula uma kuqhathaniswa ku-Oracle SQL. Yonke le nqubo ihlanganisa ukucacisa igama lomthetho osethiwe ozosuswa ngokusebenza okuthuthukisiwe "Ye-Drop Rule Set".

YEHLISA UMTHETHO WEKA imithetho_yekhasimende;

Lapha, isimiso somthetho esibizwa ngokuthi 'customer_rules' siyayekwa.

Kubalulekile ukuqaphela ukuthi ngaphambi kokuba isethi yomthetho ihoxiswe, konke ukuncika kuyo kufanele kususwe. Ukwehluleka ukwenza kanjalo kuzoholela ephutheni. Ngemuva kokuqinisekisa ukuthi akukho ukuncika, ungaqhubeka nomsebenzi.

Imitapo yolwazi Ehlobene Nemisebenzi

I-Oracle SQL inikezela ngenqwaba yemitapo yolwazi nemisebenzi engasebenza uma usebenzisa i-Drop Rule Set, njengephakheji ye-DBMS_RULE kanye nenqubo ye-DELETE RULE SET.

Iphakheji ye-DBMS_RULE iwumtapo wezincwadi onamandla onezici eziningi zokukhohlisa nokuphatha amasethi wemithetho. Inikeza onjiniyela izici eziwusizo zokuphatha amasethi wemithetho, ezisiza ekusebenzeni okushelelayo.

Inqubo ye-DELETE RULE SET, ngakolunye uhlangothi, ibandakanyeka enqubweni yokususa yamasethi wemithetho. Kuyinqubo engaphakathi kwe-Oracle SQL esetshenziselwa ukwenza imisebenzi ye-Drop Rule Set.

Funda kabanzi

I-Oracle SQL iwulimi lokuhlela olunamandla olusetshenziselwa ukuphatha amasistimu okuphatha imininingwane egciniwe (RDBMS). Namuhla, sizocubungula ngokujulile umqondo othile - umyalo we-SQL Drop Index.

Funda kabanzi

I-Oracle SQL isivumela ukuthi sisebenzise futhi siphathe idatha kusizindalwazi esihlobene. Imisebenzi evamile ihlanganisa ukubuza idatha, ukudala amathebula, nokuthuthukisa izinqubo zokucubungula idatha eziyinkimbinkimbi. Umsebenzi owodwa ovamile ofezwa onjiniyela nge-SQL ukukhetha imigqa ethile kuthebula lesizindalwazi. Kwesinye isikhathi, kungase kudingeke ukuthi sikhawulele ukuthi mangaki amarowu esiwakhethayo, ngokuvamile ngenxa yezizathu zokusebenza. Ngokuzenzakalelayo, uma ubhala isitatimende "KHETHA" ku-Oracle SQL, sithola yonke imigqa kuthebula eliqokiwe elihlangabezana nemibandela yakho. Kodwa kuthiwani uma sifuna kuphela imigqa eyi-10 yokuqala? Kulo mhlahlandlela, sizobonisa indlela yokukhetha kuphela imigqa yokuqala eyi-10 ku-Oracle SQL.

KHETHA *
KUSUKA (KHETHA *
KUSUKA etafuleni_lakho
UKUHLELA NGEkholomu_ ethile)
LAPHO ROWNUM <= 10; [/ikhodi]

Funda kabanzi

Emhlabeni wohlelo lwe-Oracle SQL, esinye sezici ezibalulekile okudingeka kubhekwane nazo, sihlanganisa ukuloga kwemicimbi noma imisebenzi ezoduduzwa. Ikhonsoli yakha ingxenye ebalulekile yokuhamba komsebenzi wokulungisa iphutha, ihlinzeka onjiniyela indlela yokulandelela ukusebenza kwesistimu, okuhlanganisa nokukhomba izindawo lapho izinkinga zingase zenzeke khona. Lesi sihloko sidingida lesi sici esibaluleke kakhulu.

Funda kabanzi

Impela, ake sikhulume ngokubuka kwe-Oracle SQL kanye namathrendi nezitayela zemfashini. Kodwa khumbula, lezi zihloko zihluke kakhulu, ngakho sizozisingatha ngokwehlukana.

I-Oracle SQL's Service Name View : Ukubuka konke

Ukubuka kwegama lesevisi kuyisici esibalulekile se-Oracle SQL. Empeleni, iwukumelwa okunengqondo kwesizindalwazi, esisebenza njengesibizo sesibonelo sesizindalwazi se-Oracle esebenzisa isevisi ethile. Lokhu kubuka kuvumela izinhlelo zokusebenza zokushaya kanye nabasebenzisi ukuthi baxhume futhi bahlanganyele nesizindalwazi ngaphandle kwesidingo segama lesibonelo esicacile.

'Ukubuka Kwegama Lesevisi' kungaxazulula izinkinga eziningi, njengokuvumela izinsiza eziningi ezihlukene ukuthi ziqondise kusizindalwazi esisodwa noma ukwenza lula ukulinganisa kokulayisha kokuxhumeka nokuhluleka.

DALA NOMA BUKEKA BHEKA amagama_amasevisi_AS
KHETHA igama, db_unique_name, network_name
KUSUKA kumasevisi we-v$;

Le khodi ye-Oracle SQL idala ukubuka kwamagama wesevisi, lapho irowu ngayinye imelela igama lesevisi elivumela ukufinyelela kusizindalwazi se-Oracle.

Libukeka Kanjani Igama Lesevisi ku-Oracle SQL?

Inqubo iqala ngokwakha umbono. Lo myalo we-Oracle SQL othi 'DALA NOMA BUYELA FUTHI' usetshenziselwa ukwakha umbono omusha, noma uma usuvele ukhona, ukuwushintsha.

Umyalo KHETHA igama, db_unique_name, network_name FROM v$services; iqoqa wonke amagama, amagama esizindalwazi esiyingqayizivele, namagama enethiwekhi ku-v$services - ukubuka kokusebenza okuguquguqukayo okubonisa ulwazi kuzo zonke izinsiza ezisebenzayo.

Ngemva kokusungulwa kokubukwa, umuntu angahlola amagama esevisi ngokwenza okujwayelekile KHETHA * FROM view_service_names; umbuzo. Umphumela uzoba uhlu lwawo wonke amagama esevisi amanje angasetshenziselwa izinjongo ezihlukahlukene.

KHETHA * KUSUKA ku-view_service_names;

Izinzuzo kanye Nezimo Zokusebenzisa Zokubuka Igama Lesevisi

Enye yezinzuzo ezibalulekile zokusebenzisa amagama esevisi ukunika amandla ukuphathwa nokulawula okulula kwesizindalwazi se-Oracle. Isibonelo, ingasiza ekuqondiseni imithwalo yomsebenzi ezimweni ezifanele zesizindalwazi futhi ilungise ukulinganisa komthwalo wokuxhumeka kohlangothi lweklayenti. Enye inzuzo ukusiza ukuhluleka kokuxhumeka ezindaweni ze-Real Application Clusters (RAC).

Funda kabanzi

Impela, Nakhu sihamba!

I-Oracle SQL iwulimi olusebenza kahle kakhulu olunikeza inkundla yokusebenzisa imiyalo ye-SQL kusizindalwazi se-Oracle. Isetshenziselwa ukuphatha kanye nokukhohlisa izinto ze-schema ezifana nokudalwa kwesizindalwazi, ukudala ukubuka, ukudala ukulandelana, ukudalwa kwegama elifanayo, nokunye ukusebenza okuyinkimbinkimbi. Kulesi sihloko, sizoxoxa ngokusebenza okukodwa okunjalo okuyisisekelo- ukwengeza ikholomu etafuleni ku-Oracle SQL.

ALTER TABLE table_name
ENGEZA uhlobo_lwekholomu_yegama;

Lona umyalo oyisisekelo ongawusebenzisa ukwengeza ikholomu kuthebula elikhona. I-syntax ihlanganisa umyalo othi “ALTER TABLE” wokushintsha ukwakheka kwetafula, uqambe ithebula ofisa ukulishintsha, umyalo othi “Engeza” otshela u-Oracle ukuthi wengeza ikholomu entsha, futhi ekugcineni igama lekholomu nesimemezelo sohlobo lwekholomu. .

Funda kabanzi