连带表间的外键关系一起删除所有某个用户下的所有表：
SELECT 'DROP TABLE '||TNAME||' CASCADE CONSTRAINT ;' FROM DBA_OBJECTS FROM DBA_OBJECTS WHERE OWNER='YOUR_USER' AND OBJECT_TYPE='TABLE'
然后将选出的结果粘贴到SQLPLUS里执行
1.查看所有用户：
select * from dba_users;
select * from all_users;
select * from user_users;
2.查看用户或角色系统权限(直接赋值给用户或角色的系统权限)：
select * from dba_sys_privs;
select * from user_sys_privs; (查看当前用户所拥有的权限)
3.查看角色(只能查看登陆用户拥有的角色)所包含的权限
sql>select * from role_sys_privs;
4.查看用户对象权限：
select * from dba_tab_privs;
select * from all_tab_privs;
select * from user_tab_privs;
5.查看所有角色： select * from dba_roles;
6.查看用户或角色所拥有的角色：
select * from dba_role_privs;
select * from user_role_privs;
7.查看哪些用户有sysdba或sysoper系统权限(查询时需要相应权限)
select * from V$PWFILE_USERS
8.SqlPlus中查看一个用户所拥有权限
SQL>select * from dba_sys_privs where grantee='username'; 其中的username即用户名要大写才行。
比如： SQL>select * from dba_sys_privs where grantee='TOM';
9、Oracle删除指定用户所有表的方法
select 'Drop table '||table_name||';' from all_tables where owner='要删除的用户名(注意要大写)';
10、删除用户
drop user user_name cascade; 如：drop user SMCHANNEL CASCADE
11、获取当前用户下所有的表：
select table_name from user_tables;
12、删除某用户下所有的表数据:
select 'truncate table ' || table_name from user_tables;
13、禁止外键 ORACLE数据库中的外键约束名都在表user_constraints中可以查到。
其中constraint_type='R'表示是外键约束。
启用外键约束的命令为：alter table table_name enable constraint constraint_name
禁用外键约束的命令为：alter table table_name disable constraint constraint_name
然后再用SQL查出数据库中所以外键的约束名：
select 'alter table '||table_name||' enable constraint '||constraint_name||';' from user_constraints where constraint_type='R'select 'alter table '||table_name||' disable constraint '||constraint_name||';' from user_constraints where constraint_type='R'
14、ORACLE禁用/启用外键和触发器 --启用脚本
SET SERVEROUTPUT ON SIZE 1000000
BEGIN
for c in (select 'ALTER TABLE '||TABLE_NAME||' ENABLE CONSTRAINT '||constraint_name||' ' as v_sql from user_constraints
where CONSTRAINT_TYPE='R') loop
DBMS_OUTPUT.PUT_LINE(C.V_SQL);
begin
EXECUTE IMMEDIATE c.v_sql;
exception when others then
dbms_output.put_line(sqlerrm);
end;
end loop;
for c in (select 'ALTER TABLE '||TNAME||' ENABLE ALL TRIGGERS ' AS v_sql from tab where tabtype='TABLE') loop
dbms_output.put_line(c.v_sql);
begin
execute immediate c.v_sql;
exception when others then
dbms_output.put_line(sqlerrm);
end;
end loop;
end;
/
commit;
--禁用脚本
SET SERVEROUTPUT ON SIZE 1000000
BEGIN
for c in (select 'ALTER TABLE '||TABLE_NAME||' DISABLE CONSTRAINT '||constraint_name||' ' as v_sql from user_constraints
where CONSTRAINT_TYPE='R') loop
DBMS_OUTPUT.PUT_LINE(C.V_SQL);
begin
EXECUTE IMMEDIATE c.v_sql;
exception when others then
dbms_output.put_line(sqlerrm);
end;
end loop;
for c in (select 'ALTER TABLE '||TNAME||' DISABLE ALL TRIGGERS ' AS v_sql from tab where tabtype='TABLE') loop
dbms_output.put_line(c.v_sql);
begin
execute immediate c.v_sql;
exception when others then
dbms_output.put_line(sqlerrm);
end;
end loop;
end;
/
commit;
15、当前连接数
select count(*) from v$process ;
16、最大连接数
select value from v$parameter where name ='processes';
17、当前所有用户，按照连接数排序
select username,count(username) as con from v$session where username is not null group by username order by con desc;
18、按执行时间排序
SELECT osuser,
a.username,
cpu_time / executions / 1000000 || 's',
sql_fulltext,
machine
from v$session a, v$sqlarea b
where a.sql_address = b.address
order by cpu_time / executions desc;