create user wyl identified by wyl;

grant create session to wyl; ?

GRANT CONNECT TO wyl;?

GRANT RESOURCE TO wyl;

GRANT DBA TO wyl;

GRANT EXP_FULL_DATABASE TO?wyl;?
GRANT IMP_FULL_DATABASE TO?wyl;?

删除用户：例如创建了一个用户 A，要删除它可以这样做?
connect sys/密码 as sysdba;?
drop user A cascade;//就这样用户就被删除了?
用户修改密码，解锁?
ALTER USER "SCOTT" IDENTIFIED BY "*******"?
ALTER USER "SCOTT" ACCOUNT UNLOCK?
1.查看所有用户：?
select * from dba_user;?
select * from all_users;?
select * from user_users;?