5. Drop a Table

The DROP TABLE command is used to delete a table along with all its rows from the database. This operation removes the table's structure and all its data, unlike deleting all records, which leaves the table's structure intact.

5.1. Usage

To delete an entire table, issue the DROP TABLE command followed by the table name:

DROP TABLE "tablename";

For example, to drop a table named myemployees_ts0211, you would use the following command:

DROP TABLE myemployees_ts0211;

5.2. Key Points

• Complete Removal: DROP TABLE removes the table definition, its data, and any associated constraints.
• Irreversible: Once a table is dropped, it cannot be recovered unless there is a backup.
• SQL Interpreter: Use an SQL interpreter or database management tool to execute the DROP TABLE command.

5.3. Exercise

Practice by dropping your employee table using the DROP TABLE command:

DROP TABLE employee;

5.4. Effects of Dropping a Table

When a table is dropped, the following happens:

• Data Loss: All data contained in the table is permanently deleted.
• Index Removal: Any indexes associated with the table are also removed.
• Constraint Deletion: All constraints such as primary keys, foreign keys, and unique constraints are deleted.
• Dependency Impact: Any views, stored procedures, or functions that reference the dropped table may become invalid.

5.5. Precautions

• Backup Data: Ensure you have a backup of the data before dropping the table if needed for future reference.
• Check Dependencies: Verify any dependencies or relationships the table might have with other database objects.
• Confirm Operation: Double-check the table name to avoid accidental data loss.