Testing - Difference between Delete, Truncate and Drop commands on SQL

Difference between TRUNCATE, DELETE and DROP commands

a.       The DELETE command is used to remove rows from a table. A WHERE clause can be used to only remove some rows. If no WHERE condition is specified, all rows will be removed. After performing a DELETE operation you need to COMMIT or ROLLBACK the transaction to make the change permanent or to undo it. Note that this operation will cause all DELETE triggers on the table to fire.

b.      TRUNCATE removes all rows from a table. The operation cannot be rolled back and no triggers will be fired. As such, TRUCATE is faster and doesn't use as much undo space as a DELETE.

a.       TRUNCATE is a DDL command whereas DELETE is a DML command.

b.      TRUNCATE is much faster than DELETE.

c.       DELETE command moves data to rollback Table space first. Then delete operation get performed when committed

d.      Type ROLLBACK after deleting a table, you can get back the data (The system get it for you from the Rollback Tablespace).

e.       When you type TRUNCATE, it removes data directly without copying it into the Rollback Tablespace.Thatswhy TRUNCATE is faster. Once you Truncate you cann't get back the data.

f.        You cann't rollback in TRUNCATE but in DELETE you can rollback.TRUNCATE removes the record permanently.

c.       You can't use conditions(WHERE clause) in TRUNCATE. But in DELETE you can write conditions using WHERE clause

d.      The DROP command removes a table from the database. All the tables' rows, indexes and privileges will also be removed. No DML triggers will be fired. The operation cannot be rolled back.