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Video: Dab tsi yog qhov txawv ntawm SQL thiab database?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
KEV SIJ HAWM :
SQL ntawv yog ib hom lus uas siv los khiav koj database whereas MySQL yog ib qho ntawm thawj qhov chaw qhib database muaj hauv kev ua lag luam. SQL ntawv yog siv hauv nkag mus, hloov kho, thiab tswj cov ntaub ntawv hauv adatabase thaum MySQL yog RDBMS uas tso cai rau khaws cov ntaub ntawv uas muaj hauv database
Tsis tas li ntawd, SQL yog dab tsi hauv database?
SQL ntawv (hais "ess-que-el") sawv cev rau Cov Lus Nug Lus Nug. SQL ntawv cov nqe lus yog siv los ua cov haujlwm xws li hloov kho cov ntaub ntawv ntawm a database , los yog retrievedata los ntawm a database . Qee qhov kev sib raug zoo database tswj systems uas siv SQL ntawv yog: Oracle, Sybase, Microsoft SQL ntawv Server, Access, Ingres, thiab lwm yam.
Ib yam li ntawd, SQL puas yog qhov system? sˌkjuːˈ?l/ (mloog) S-Q-L , /ˈsiːkw?l/ "sequel"; Structured QueryLanguage) yog ib hom lus tshwj xeeb uas siv hauv programming thiab tsim los tswj cov ntaub ntawv tuav hauv kev sib raug zoo database tswj qhov system (RDBMS), los yog rau kev ua cov kwj dej hauv kev tswj hwm cov ntaub ntawv sib raug zoo qhov system (RDSMS).
Ib yam li ntawd, tib neeg nug, qhov txawv ntawm SQL thiab NoSQL databases yog dab tsi?
Ntsiab Qhov sib txawv ntawm SQL thiab NoSQL SQL Database yog Relational Database anda structured ib qhov whereas NoSQL yog tsis muaj kev sib raug zoo database yuav ua tau ntau cov ntaub ntawv thiab faib ntau tshaj li qauv. SQL databases yog vertically scalable whereas NoSQL databases yog horizontallyscalable.
Cov kev pab cuam twg siv SQL?
Qee qhov kev paub zoo tshaj plaws database software program suav nrog:
- ADABAS.
- IB DB2.
- Microsoft Access.
- Microsoft Excel.
- Microsoft SQL Server.
- MySQL.
- Oracle RDBMS.
- Ceev Base.
Pom zoo:
Dab tsi yog qhov txawv ntawm qhov sib txawv hauv zos thiab thoob ntiaj teb hauv SQL Server?
Qhov sib txawv hauv zos tau tshaj tawm hauv ib qho kev ua haujlwm whereas Ntiaj teb hloov pauv tau tshaj tawm sab nraum lub luag haujlwm. Cov kev hloov hauv zos tau tsim thaum lub luag haujlwm tau pib ua tiav thiab ploj thaum lub luag haujlwm xaus, ntawm qhov tod tes, Ntiaj teb hloov pauv yog tsim raws li kev tua pib thiab ploj thaum qhov kev pab cuam xaus
Dab tsi yog qhov sib txawv ntawm lub thawv thiab lub thawv ntawv thiab lub thawv ntawv yog dab tsi?
Ib lub thawv thiab cov ntawv nplawm (qee zaum hu ua boxplot) yog ib daim duab uas nthuav tawm cov ntaub ntawv los ntawm tsib lub ntsiab lus. Nyob rau hauv ib lub thawv thiab whisker zajlus: qhov kawg ntawm lub thawv yog lub sab sauv thiab sab quartiles, yog li lub thawv spans lub interquartile ntau yam. qhov nruab nrab yog cim los ntawm ib txoj kab ntsug hauv lub thawv
Dab tsi yog qhov txawv ntawm cov ntaub ntawv hom thiab qhov sib txawv?
Ib qho kev sib txawv yuav tsum muaj cov ntaub ntawv sib txuas nrog nws, piv txwv li nws tuaj yeem muaj cov ntaub ntawv xws li cov lej, lej lej, cov cim thiab lwm yam. Qhov sib txawv ntawm hom Integer khaws cov lej suav thiab tus cim typevariable khaws cov cim tus nqi. Thawj qhov sib txawv ntawm ntau hom ntaub ntawv yog lawv qhov loj me me
Dab tsi yog qhov zoo sib xws thiab qhov txawv ntawm relays thiab PLC yog dab tsi?
Relays yog electro-mechanical keyboards uas muaj coil thiab ob hom kev sib cuag uas tsis yog NO & NC. Tab sis Programmable Logic Controller, PLC yog lub khoos phis tawj me uas tuaj yeem txiav txim siab raws li qhov kev zov me nyuam thiab nws cov tswv yim & tso tawm
Dab tsi yog qhov sib txawv ntawm qhov ntsuas qhov ntsuas thiab qhov ntsuas thib ob?
Primary index: nyob rau hauv ib tug sequentially order file, qhov Performance index uas nws search key qhia cov sequential order ntawm cov ntaub ntawv. Kuj hu ua clustering index. Secondary index: ib qho Performance index uas nws qhov tseem ceeb tshawb nrhiav qhia qhov kev txiav txim sib txawv ntawm qhov kev txiav txim ntawm cov ntaub ntawv. Kuj hu ua non-clustering index