What is difference between DELETE & TRUNCATE commands?


Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.

TRUNCATE

  • TRUNCATE is faster and uses fewer system and transaction log resources than DELETE.
  • TRUNCATE removes the data by deallocating the data pages used to store the table‚Äôs data, and only the page deallocations are recorded in the transaction log.
  • TRUNCATE removes all rows from a table, but the table structure, its columns, constraints, indexes and so on, remains. The counter used by an identity for new rows is reset to the seed for the column.
  • You cannot use TRUNCATE TABLE on a table referenced by a FOREIGN KEY constraint. Because TRUNCATE TABLE is not logged, it cannot activate a trigger.
  • TRUNCATE cannot be rolled back.
  • TRUNCATE is DDL Command.
  • TRUNCATE Resets identity of the table

DELETE

  • DELETE removes rows one at a time and records an entry in the transaction log for each deleted row.
  • If you want to retain the identity counter, use DELETE instead. If you want to remove table definition and its data, use the DROP TABLE statement.
  • DELETE Can be used with or without a WHERE clause
  • DELETE Activates Triggers.
  • DELETE can be rolled back.
  • DELETE is DML Command.
  • DELETE does not reset identity of the table.