Quick Answer:
- DELETE removes specific rows from a table (can use
WHERE), keeps structure, and is a DML command. - TRUNCATE removes all rows quickly, resets identity counters, but keeps the table structure; it’s a DDL command.
- DROP removes the entire table (structure + data) permanently; it’s also a DDL command.
🔎 Detailed Comparison of DELETE, TRUNCATE, and DROP
| Feature | DELETE | TRUNCATE | DROP |
|---|---|---|---|
| Type | DML (Data Manipulation Language) | DDL (Data Definition Language) | DDL (Data Definition Language) |
| Purpose | Removes specific rows (with WHERE) |
Removes all rows, keeps structure | Removes entire table (data + schema) |
| Syntax | DELETE FROM table WHERE condition; |
TRUNCATE TABLE table_name; |
DROP TABLE table_name; |
| Condition Support | Yes (WHERE clause) |
No (always deletes all rows) | Not applicable |
| Rollback | Possible if inside a transaction | Possible in some DBs (depends) | Not possible once executed |
| Speed | Slower (logs each row deletion) | Faster (minimal logging) | Fast (removes metadata + data) |
| Identity Reset | No | Yes (resets auto-increment counters) | Not applicable |
| Table Structure | Retained | Retained | Removed |
| Use Case | Delete selective records | Clear all records quickly | Remove table permanently |
⚡ Key Points to Remember
- DELETE is row-level and can be selective. Best when you need to remove some data.
- TRUNCATE is bulk removal, faster, but cannot filter rows. Best when you want a clean slate but keep the table.
- DROP is destructive — removes the table definition itself. Best when you no longer need the table at all.
🧠 Interview Tip for You (Brijendra)
Since you’re preparing for senior Java/architect roles, interviewers often ask this to test database fundamentals and performance awareness. A strong answer would highlight:
- DELETE → flexible but slower due to logging.
- TRUNCATE → faster, resets identity, cannot filter.
- DROP → removes schema, irreversible.
You can also mention transaction behavior: DELETE can be rolled back easily, TRUNCATE depends on DB engine, DROP is final.
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