Video: DCL hais kom ua hauv SQL yog dab tsi?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
Cov ntaub ntawv tswj hom lus ( DCL ) yog syntax zoo ib yam li lub khoos phis tawj programming lus siv los tswj kev nkag mus rau cov ntaub ntawv khaws cia hauv database (Kev tso cai). Tshwj xeeb, nws yog ib feem ntawm Structured Query Language ( SQL ntawv ). Piv txwv ntawm DCL cov lus txib suav nrog: GRANT tso cai rau cov neeg siv tshwj xeeb los ua cov haujlwm tshwj xeeb.
Cov lus nug tseem yog, qhov twg yog DCL hais kom ua hauv SQL?
DCL (Data Control Language): DCL suav nrog lus txib xws li GRANT thiab REVOKE uas feem ntau cuam tshuam nrog cov cai, kev tso cai thiab lwm yam kev tswj hwm ntawm qhov system database. Piv txwv ntawm DCL cov lus txib : GRANT-muab cov neeg siv txoj cai nkag mus rau cov ntaub ntawv. REVOKE- thim tus neeg siv cov cai nkag tau muab los ntawm kev siv GRANT lus txib.
Qhov thib ob, DML thiab DCL yog dab tsi? DDL yog Data Definition Language. DML yog Data Manipulation Language. DCL yog Data Control Language.
Ua raws li qhov no saib, DCL thiab TCL cov lus txib hauv SQL yog dab tsi?
DCL yog luv ntawm Data Control Language. Nws yog siv los tsim lub luag haujlwm, kev tso cai, thiab kev lees paub ncaj ncees zoo li nws yog siv los tswj kev nkag mus rau hauv database los ntawm kev ruaj ntseg. TCL yog luv luv ntawm Transactional Control Language. Nws yog siv los tswj cov kev hloov pauv sib txawv uas tshwm sim hauv ib lub database.
Daim ntawv tag nrho ntawm DCL yog dab tsi?
Cov Ntaub Ntawv Tswj Lus
Pom zoo:
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