[Concept Entry] TRUCATE in SQL

content/sql/concepts/commands/terms/truncate/truncate.md

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+---
+Title: 'TRUNCATE'
+Description: 'Deletes all rows from a table while retaining the table structure.'
+Subjects:
+  - 'Data Science'
+  - 'Data Visualization'
+Tags:
+  - 'Data'
+  - 'Database'
+  - 'Functions'
+  - 'SQL'
+CatalogContent:
+  - 'learn-sql'
+  - 'paths/analyze-data-with-sql'
+---
+
+**`TRUNCATE`** is a SQL statement used to quickly delete all rows from a table while retaining the table structure. Unlike the **`DELETE`** statement, `TRUNCATE` does not log individual row deletions and does not generate triggers, making it faster for large datasets.
+
+## Key Characteristics
+
+- _Performance_: `TRUNCATE` is more efficient than `DELETE` because it uses minimal logging.
+- _Data Integrity_: It resets identity columns (e.g., `AUTO_INCREMENT`) to their seed values.
+- _Irreversibility_: `TRUNCATE` operations cannot be rolled back in most database systems, as it does not log row-level changes.
+- _Constraints_: Cannot truncate a table that is referenced by a foreign key.
+
+## Comparison: TRUNCATE vs. DELETE
+
+| Feature               | `TRUNCATE`                    | `DELETE`                  |
+| --------------------- | ----------------------------- | ------------------------- |
+| Row Logging           | No                            | Yes                       |
+| Triggers              | Not activated                 | Activated                 |
+| Rollback              | Not supported in many systems | Supported                 |
+| Identity Column Reset | Yes                           | No                        |
+| Performance           | Faster                        | Slower for large datasets |
+
+## Syntax
+
+```pseudo
+TRUNCATE TABLE table_name;
+```
+
+- `table_name`: Specifies the name of the table to truncate.
+
+> **Note:** Use `TRUNCATE` carefully in production environments, as it cannot be undone.
+
+## Example
+
+The `TRUNCATE` statement can be used to clear all records from a table while retaining its structure. For instance, to remove all data from a table named `employee_data`:
+
+```sql
+TRUNCATE TABLE employee_data;
+```
+
+This removes all rows from the `employee_data` table without affecting the table's schema or structure.