Drop means removing.Removing the existence.

Truncate - there is no log maintained for the deleted
records.As when we perform delete a log is maintained a slow
process.

Drop means removing the existing object from the database.
turncate means you are deleting the data from the table and 
oracle implicitly issues commit statment and even when you 
say rollback , you won't get the data back due to commit ..

Drop will delete all the existing structure. if it applies 
to a table, Truncate will delete only the data while 
keeping the structure of the table as it is.

Drop and Truncate commands both are DML commands.
If we use drop command it will deletes all the table data 
as well as tablestructure.But if we use truncate command it 
will deletes the table data only.

TRUNCATE: Only data is deleted structure of the table 
exists.


DROP:  Both data and structure of the table gets removed.

DROP means it's drop the table(with rows,Pk_key, Fk_key and 
indexces)from the database.
TRUNCATE do the same as DROP but maintain the Pk_key, 
Fk_key and indexces declaration only remove rows.

---by suman kalyan betal (suman_kal@rediffmail.com)

Drop can be used to drop the entire table including data 
and structure of table where as truncate removes rows from 
table but the structure of table remains as it is.

both are ddl commands.Drop deletes the table with schema 
and records but truncate deletes only records.Drop can be 
roll back but not truncate.

Truncate removes data permanently while drop does not,we 
can rollback in case of drop.

Triggers does not get fired , in case of truncate ,but in 
drop it gets fired.
truncate is much faster than drop

drop will remove the entire table from the database and can
be rollbacked.

truncate will remove the content of the table and it cannot
be rollbacked.

truncate is little bit faster than drop.