Cov txheej txheem:
- Muaj tsib hom SQL Commands uas tuaj yeem faib ua:
- Cov lus txib SQL no feem ntau yog categorized intofourcategories li:
Video: Dab tsi yog qhov sib txawv SQL commands?
2024 Tus sau: Lynn Donovan | [email protected]. Kawg hloov kho: 2023-12-15 23:47
SQL lus txib tau muab faib ua plaub pawg nyob ntawm lawv qhov kev ua haujlwm: DataDefinitionLanguage (DDL) - Cov no SQL lus txib yog siv forcreating, hloov kho, thiab xa me nyuam rov cov qauv ntawm database objects. The lus txib yog CREATE, ALTER, DROP, RENAME, thiab TRUNCATE.
Tsis tas li, ntau hom SQL commands yog dab tsi?
Muaj tsib hom SQL Commands uas tuaj yeem faib ua:
- DDL (Data txhais lus).
- DML (Data Manipulation Language).
- DQL (Data Query Language).
- DCL (Data Control Language).
- TCL (Kev Tswj Kev Lag Luam).
Kuj Paub, muaj pes tsawg cov lus txib nyob hauv SQL? SQL lus txib : Ntau Hom KeysInDatabase Nyob ntawd Feem ntau yog 7 hom Keys, uas tuaj yeem txiav txim siab hauv cov ntaub ntawv.
Ib yam li ntawd, nws yog nug, dab tsi yog qhov yooj yim SQL commands?
- Database. Lub database muaj ib lossis ntau lub rooj.
- Basic SQL. Txhua cov ntaub ntawv muaj ib tus cim tshwj xeeb orprimarykey.
- Xaiv. SELECT yog siv los nug cov ntaub ntawv thiab khaws cov ntaub ntawv uas raug xaiv raws li cov txheej txheem tshwj xeeb uas koj tau hais tseg:
- CEEB TOOM.
- INSERT VALUES.
- Hloov tshiab.
- DELETE.
- DROP.
Plaub pawg ntawm SQL commands yog dab tsi?
Cov lus txib SQL no feem ntau yog categorized intofourcategories li:
- DDL - Cov Lus Txhais Lus.
- DQl - Cov ntaub ntawv nug lus.
- DML – Data Manipulation Language.
- DCL - Cov Ntaub Ntawv Tswj Cov Lus.
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