MYDBA@ORCL >
MYDBA@ORCL > create user b identified by b;

User created.

MYDBA@ORCL > grant create session, resource, connect to b;

Grant succeeded.

MYDBA@ORCL > connect b/b;
Connected.
B@ORCL > create table test(a number);

Table created.

B@ORCL > connect mydba/orcl
Connected.
MYDBA@ORCL > drop user b;
drop user b
*
ERROR at line 1:
ORA-01922: CASCADE must be specified to drop 'B'


MYDBA@ORCL > set timing on
MYDBA@ORCL > drop user b cascade;

User dropped.

Elapsed: 00:00:19.06
MYDBA@ORCL > create user b identified by b;

User created.

Elapsed: 00:00:00.04
MYDBA@ORCL > set timing off
MYDBA@ORCL > grant connect, resource to b;

Grant succeeded.

MYDBA@ORCL > connect b/b;
Connected.
B@ORCL > create table test(a number);

Table created.

B@ORCL > set timing on;
B@ORCL > drop table test;

Table dropped.

Elapsed: 00:00:00.57
B@ORCL > connect mydba/orcl
Connected.
Elapsed: 00:00:00.01
Elapsed: 00:00:00.01
MYDBA@ORCL > drop user b;

User dropped.

Elapsed: 00:00:00.83
MYDBA@ORCL > set timing off
MYDBA@ORCL > select * from v$version;

BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Prod
PL/SQL Release 10.1.0.4.0 - Production
CORE    10.1.0.4.0      Production
TNS for 32-bit Windows: Version 10.1.0.4.0 - Production
NLSRTL Version 10.1.0.4.0 - Production

5 rows selected.

MYDBA@ORCL >

SCOTT@teng>drop table emp purge;