1.
DELETE :
Basically, it is a Data Manipulation Language Command (DML). It is use to delete
the one or more tuples of a table. With the help of “DELETE” command we can
either delete all the rows in one go or can delete row one by one. i.e., we can
use it as per the requirement or the condition using Where clause. It is
comparatively slower than TRUNCATE cmd.
DELETE from ;
DELETE from
WHERE ;
Note – Here we can use the “ROLLBACK”
command to restore the tuple.
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2. DROP
:
It is a Data Definition Language Command (DDL). It is use to drop the whole
table. With the help of “DROP” command we can drop (delete) the whole structure
in one go i.e. it removes the named elements of the schema. By using this
command the existence of the whole table is finished or say lost.
DROP table
;
Note – Here we can’t restore the table
by using the “ROLLBACK” command.
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3. TRUNCATE :
It is also a Data Definition Language Command (DDL). It is use to delete all
the rows of a relation (table) in one go. With the help of “TRUNCATE” command
we can’t delete the single row as here WHERE clause is not used.
By using this
command the existence of all the rows of the table is lost. It is comparatively
faster than delete command as it deletes all the rows fastly.
TRUNCATE tablename;
Note –
Here we can’t restore the tuples
of the table by using the “ROLLBACK” command
