Which operation efficiently removes a large number of records from a table when conditions are met?

Which operation efficiently removes a large number of records from a table when conditions are met?

• A. DROP TABLE
• B. DELETE FROM table WHERE condition
• C. SELECT
• D. ALTER TABLE

Answer: (B)

Deleting rows with a conditional clause targets only the records that meet the criteria, while preserving the table structure and constraints. This DELETE statement with a WHERE condition is efficient for removing a large number of records because the database can use indexes on the condition to quickly locate and remove the matching rows, often within a single transaction and with controllable logging. It also allows for proper handling of related data (via foreign keys or cascading deletes) and rollback if needed. In contrast, dropping the table would remove the entire table, selecting doesn’t modify data, and altering the table changes the schema rather than removing rows.

Deleting rows with a conditional clause targets only the records that meet the criteria, while preserving the table structure and constraints. This DELETE statement with a WHERE condition is efficient for removing a large number of records because the database can use indexes on the condition to quickly locate and remove the matching rows, often within a single transaction and with controllable logging. It also allows for proper handling of related data (via foreign keys or cascading deletes) and rollback if needed. In contrast, dropping the table would remove the entire table, selecting doesn’t modify data, and altering the table changes the schema rather than removing rows.