CUET PG 2021 — Computer PYQ

Explanation

SQL commands ko unke kaam ke hisaab se categories mein baata gaya hai. Table delete karne ka logic samajhne ke liye niche diye gaye points dekhiye:

• DROP Command: Yeh command database se table ka structure (schema) aur uske andar ka saara data permanent taur par mita deta hai.

  $$\text{DROP}⟹\text{Delete Structure}+\text{Delete Data}$$

• DELETE Command: Yeh sirf table ke andar ki rows (records) ko delete karne ke liye hota hai, table ka structure bana rehta hai.

  $$\text{DELETE}⟹\text{Delete Data Rows only}$$

• TRUNCATE Command: Yeh table ke saare data ko ek saath saaf kar deta hai, lekin table (structure) khali rehta hai.

  $$\text{TRUNCATE}⟹\text{Clear all rows (faster than DELETE)}$$

Comparison Table

Feature	DROP	DELETE	TRUNCATE
Type	DDL (Data Definition)	DML (Data Manipulation)	DDL (Data Definition)
Structure	Structure hat jata hai	Structure bacha rehta hai	Structure bacha rehta hai
Undo (Rollback)	Mumkin nahi (zyadatar)	Mumkin hai	Mumkin nahi

Syntax Example

Agar aapko "Students" naam ki table delete karni hai, toh aap ye query likhenge: