Cov txheej txheem:
- Yuav ua li cas sib koom ua ke tso cai duplicates?
- Peb puas tuaj yeem tsim qhov ntsuas tsis yog pawg ntawm cov kab tsis tshwj xeeb?
- Dab tsi yog qhov tsis sib xws?
- Can clustered index muaj nuj nqis?
- Unique and Non Unique Indexs in sql server Part 37
2024 Tus sau: Simon Evans | [email protected]. Kawg hloov kho: 2024-01-13 03:51
Ob pawg thiab tsis suav nrog tuaj yeem yog qhov tshwj xeeb. Qhov no txhais tau tias tsis muaj ob kab tuaj yeem muaj tus nqi tib yam rau tus yuam sij index. Txwv tsis pub, qhov Performance index tsis yog qhov tshwj xeeb thiab ntau kab tuaj yeem faib cov nqi tseem ceeb. Yog xav paub ntxiv, saib Tsim Cov Ntawv Qhia Tshwj Xeeb.
Yuav ua li cas sib koom ua ke tso cai duplicates?
Yog, koj tuaj yeem tsim qhov ntsuas ntsuas ntawm cov kab tseem ceeb uas muaj qhov sib npaug. … Piv txwv li, tej zaum koj yuav txiav txim siab los tsim ib qho kev ntsuas ntawm pawg LastName ntawm lub rooj uas muaj cov neeg siv khoom cov ntaub ntawv.
Peb puas tuaj yeem tsim qhov ntsuas tsis yog pawg ntawm cov kab tsis tshwj xeeb?
Yog li, thaum koj tsim qhov ntsuas qhov ntsuas - nws yuav tsum yog qhov tshwj xeeb. Tab sis, SQL Server tsis xav kom koj tus yuam sij clustering yog tsim rau ntawm ib kab tshwj xeeb. Koj tuaj yeem tsim nws ntawm txhua kab(s) koj xav tau. Internally, yog hais tias tus yuam sij clustering tsis tshwj xeeb ces SQL Server yuav "uniquify" nws los ntawm kev ntxiv ib tug 4-byte integer rau cov ntaub ntawv.
Dab tsi yog qhov tsis sib xws?
Thaum koj tsim ib qho kev txwv UNIQUE, qhov tshwj xeeb tsis suav nrog qhov ntsuas yog tsim los tswj kev txwv UNIQUE los ntawm lub neej ntawdKoj tuaj yeem hais qhia qhov sib txawv tshwj xeeb yog qhov ntsuas ntsuas ntawm lub rooj ua tsis muaj lawm. Yog xav paub ntxiv, mus saib Cov Kev Txwv Tshwj Xeeb thiab Tshawb Xyuas Cov Kev Txwv.
Can clustered index muaj nuj nqis?
Rau qhov ntsuas qhov ntsuas, kab ntawv tsis tas yuav yog qhov tshwj xeeb thiab / lossis tsis muaj null. Ib kem nrog duplicates thiab null qhov tseem ceeb yog qhov zoo rau kev tsim kom muaj kev sib koom ua ke. Rau tus yuam sij txawv teb chaws, nws yuav tsum tau hais txog ib kab nrog cov cim tshwj xeeb ntawm nws tab sis tsis tas yuav yog tus yuam sij tseem ceeb lossis tsis muaj nuj nqis.
Pom zoo:
Dab tsi yog qhov txawv ntawm kev sau tsis raug thiab sau tsis raug?
"Ua tsis raug" thiab "misspelt" yog ob leeg sau nrog ib ob "s." Thawj "s" yog los ntawm prefix "mis," thiab qhov thib ob yog los ntawm lo lus hauv paus "spell." Yog tias koj tsis paub meej seb puas siv "
Tus kws kho mob yuav coj txawv txawv 2 r?
MCU yog ib tsev neeg-taw qhia, tom qab tag nrho (kom txog rau thaum Deadpool 3 tuaj txog, tej zaum?), yog li tsis txhob cia siab tias tus kws kho mob txawv txawv 2 yuav raug ntsuas R lossis dab tsi zoo li ntawd. … Tus kws kho mob txawv txawv hauv ntau qhov kev npau taws yuav raug tso tawm ua yeeb yam thaum Lub Peb Hlis 25, 2022 .
Yuav ua li cas coj txawv txawv thor?
Nyob rau hauv kev sib ntaus sib tua surprise, Thor yuav txiav txim siab tus kws kho mob txawv txawvnrog nws lub zog siab phem thiab ua haujlwm ntev. Txawm li cas los xij, muab lub sijhawm npaj, Coj txawv txawv tsuas muaj ntau qhov kev dag ntxias ntawm nws lub tes tsho tej yam yees siv, thiab nws yuav nyuaj rau leej twg los yeej nws, txawm tias Thor hauv nws daim ntawv muaj zog tshaj .
Yuav ua li cas thaum kawg ntawm kev coj txawv txawv tab sis muaj tseeb?
Ntxim tab sis Muaj tseeb kawg piav thaum kawg peb pom tias Melissa yug tau tus menyuam uas tau txais tos los ntawm tsev neeg Ronnie … Thaum lub sijhawm kawm zaj yeeb yaj kiab, nws tau nthuav tawm tias Melissa tau txais los ntawm ob niam txiv laus, Bill thiab Gail, tom qab Ronnie ntsib kev sib tsoo .
Dab tsi yog qhov txawv ntawm qhov tsis sib xws thiab tsis yog qhov txawv?
Cov tsev kawm ntawv qib siab thoob plaws lub tebchaws siv cov lus "tseem ceeb" thiab "tsis yog ib txwm siv," hais txog hnub nyoog ntawm cov tub ntxhais kawm. Tsis yog ib txwm nyiam kom muaj hnub nyoog 24 xyoos nce, thaum cov tsoos yog cov cai tawm hauv tsev kawm theem siab .