Video: Puas yog SQL ceev?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
SQL ntawv yog ceev vim tias cov ntaub ntawv tuaj yeem txiav txim siab kom tau txais cov ntaub ntawv. Tej zaum koj yuav tau ua qee qhov kev hloov kho, piv txwv li, koj yuav tsum tau tsim cov indexes lossis cov partitions. Tab sis lub kaw lus feem ntau ua haujlwm zoo ntawm kev xaiv cov phiaj xwm ua tau zoo tshaj plaws rau txhua qhov lus nug. SQL ntawv yog ib hom lus siab heev.
Tib neeg kuj nug, yog SQL lossis NoSQL sai dua?
Feem ntau, NoSQL tsis yog sai dua tshaj SQL ntawv ib yam li SQL ntawv tsis yog sai dua tshaj NoSQL . Ntawm qhov tod tes, NoSQL cov databases tshwj xeeb yog tsim los rau cov ntaub ntawv tsis muaj teeb meem uas tuaj yeem ua cov ntaub ntawv-oriented, kem-oriented, graph-based, thiab lwm yam. Nyob rau hauv cov ntaub ntawv no, ib qho chaw tshwj xeeb cov ntaub ntawv khaws cia ua ke thiab tsis muab faib.
Ib sab saum toj no, kuv tuaj yeem ua kom ceev cov lus nug SQL li cas? Peb tau ua cov npe ntawm 17 txoj hauv kev uas koj tuaj yeem xav txog txhawm rau txhim kho koj cov lus nug SQL.
- Siv cov npe ntawm cov npe tsis yog * hauv SELECT nqe lus.
- Sim tsis txhob siv HAVING clause hauv SELECT nqe lus.
- Tsis txhob siv UPDATE es tsis yog CASE.
- Tsis txhob dig muag rov siv Code.
- Siv ib qho IN predicate thaum nug ib kab indexed.
Ntxiv mus, uas koom nrog yog nrawm dua hauv SQL?
Zoo, feem ntau PIB HAIV NEEG yuav sai dua vim tias nws tsuas yog rov qab cov kab sib tw hauv txhua lub rooj sib koom ua ke raws li cov kab sib koom. Tab sis LEFT JOIN yuav rov qab tag nrho cov kab los ntawm cov lus teev tseg LEFT thiab tag nrho cov kab sib txuam los ntawm lub rooj teev tseg RIGHT.
Vim li cas MongoDB sai dua SQL?
MongoDB yooj yim teeb tsa, teeb tsa, thiab khiav hauv kev sib piv rau RDBMS. MongoDB siv lub cim xeeb sab hauv los khaws cov khoom ua haujlwm uas ua rau sai dua siv sijhawm. MongoDB txhawb kev sib sib zog nqus query-muaj peev xwm xws li peb tuaj yeem ua cov lus nug dynamic ntawm cov ntaub ntawv siv cov ntaub ntawv raws li cov lus nug uas yuav luag muaj zog li SQL ntawv.
Pom zoo:
Puas yog WiFi teeb liab muaj zog cuam tshuam kev rub tawm ceev?
3 Teb. Koj lub internet ceev yog ywj siab ntawm koj lub zog Wifi. Tam sim no rau kab thib ob - Koj lub zog Wifi tej zaum yuav cuam tshuam rau internet ceev koj pom. yog vim Wifi yog li cas koj tau txais cov ntaub ntawv rau lub computer. Thaum koj txav deb ntawm lub router lub teeb liab ntawm nws thiab koj lub computer degrades
Puas yog kev pab ceev ntawm Windows 7?
Yog tias koj ob leeg siv Windows 10, koj tuaj yeem siv lub built-in "Quick Assist" app ua qhov no. Yog tias ib tus ntawm koj siv Windows 7 lossis 8, koj tuaj yeem siv Windows Remote Assistance qub. Windows Remote Assistance tseem suav nrog Windows 10, tsuas yog thaum koj xav tau
Puas yog react haiv neeg ceev?
React-Native tuaj yeem sau rau hauv Javascript (ib hom lus ntau tus neeg tsim khoom twb paub lawm), nws cov codebase tuaj yeem xa mus rau ob qho tib si iOS thiab Android platforms, nws sai dua thiab pheej yig dua los tsim cov apps, thiab cov neeg tsim khoom tuaj yeem thawb hloov kho ncaj qha rau cov neeg siv kom cov neeg siv khoom. tsis tas yuav txhawj txog kev rub tawm tshiab
Muaj pes tsawg lub cuab yeej tuaj yeem txuas nrog lub tshuab hluav taws xob ceev ceev thiab dav SCSI?
Fast Wide lossis Ultra Wide tuaj yeem hais txog 15 khoom siv. - Ultra Narrow lossis Ultra Wide yog txwv rau 1.5 Meters hauv cable ntev nrog plaub lossis ntau dua
Puas yog j7 2016 txhawb kev them nyiaj ceev?
Nqe Lus Nug- Puas yog Kev them nyiaj ceev txhawb nqa hauv Samsung Galaxy J7 (2016)? Teb- Tsis yog, kev them nyiaj ceev tsis muaj nyob hauv lub xov tooj no