1. Dab tsi yog qhov subset ntawm SQL cov lus txib siv los tswj Oracle Database cov qauv, suav nrog cov ntxhuav? Nqe lus piav qhia: The DDL yog siv los tswj cov lus thiab cov qauv ntsuas. CREATE, ALTER, RENAME, DROP thiab TRUNCATE cov nqe lus yog cov npe ntawm ob peb cov ntaub ntawv txhais ntsiab lus.
Qhov twg SQL cov lus txib yog siv los tswj cov qauv ntawm cov khoom siv database?
Data Definition Language (DDL) - Cov lus txib SQL no yog siv los tsim, hloov kho, thiab tso cov qauv ntawm cov khoom siv database. Cov lus txib yog CREATE, ALTER, DROP, RENAME, thiab TRUNCATE.
Qhov twg ntawm SQL cov lus txib tuaj yeem siv los tswj cov rooj lossis cov ntaub ntawv?
Data Manipulation Language yog siv los tswj cov ntaub ntawv hauv cov ntxhuav. Cov lus txib yooj yim DML hauv SQL yog Insert, Update and Delete.
Cov lus txib twg yog siv los tswj cov ntaub ntawv hauv database ?
Data Manipulation Commands hauv DBMS
- Xaiv. Xaiv nqe lus retrieves cov ntaub ntawv los ntawm database raws li cov kev txwv qhia ib sab. …
- Insert. Insert nqe lus yog siv los ntxig cov ntaub ntawv rau hauv cov ntxhuav database. …
- Update. Cov lus txib hloov tshiab hloov kho cov ntaub ntawv uas twb muaj lawm hauv ib lub rooj. …
- delete. …
- Merge.
Dab tsi yog subset hauv SQL?
Cov ntau yam ntawm SQL muaj raws li hauv qab no: DDL (Cov Ntaub Ntawv Txhais Lus) - Nws tso cai rau koj musua ntau yam haujlwm ntawm cov ntaub ntawv xws li CREATE, ALTER thiab DELETE cov khoom. … DCL (Data Control Language) – Nws tso cai rau koj los tswj kev nkag mus rau hauv cov ntaub ntawv. Piv txwv – Grant, Revoke access permissions.
