TRUNCATE and DELETE are two SQL commands used to delete data from a table. Both commands remove rows from a table, but there are important differences between them. TRUNCATE is a Data Definition Language (DDL) command that deletes all rows or tuples from a table without a WHERE clause. It is fast and does not record the deletion of each row in the transaction log.
On the other hand, DELETE is a Data Manipulation Language (DML) command that can conditionally delete data with a WHERE clause. It is slower than TRUNCATE and records the deletion of each row in the transaction log. DROP TABLE is another DDL operation that removes the table structure from the database, along with the data stored in the table. The TRUNCATE command is used to delete all rows from a table, while DELETE can be used to delete specific data. With the DELETE command, we cannot bypass the integrity enforcement mechanisms.
TRUNCATE can be reversed as long as it is included in a TRANSACTION block and the session is not closed. However, DELETE cannot be reversed once committed. Understanding the differences between these commands helps SQL developers manage their data well. It is also a very common question asked in SQL beginner interviews. Knowing when to use TRUNCATE or DELETE can help you optimize your database performance and maintain data integrity.