oracle恢復誤刪除資料

醉面韋陀發表於2010-05-07

1.曾經不小心把開發庫的資料庫表全部刪除,當時嚇的要死。結果找到下面的語句恢復到了1個小時之前的資料!很簡單。

注意使用管理員登入系統:

select * from 表名 as of timestamp sysdate-1/12   //查詢兩個小時前的某表資料!既然兩小時以前的資料都得到了,繼續怎麼做,知道了吧。。

 

如果drop了表,怎麼辦??見下面:

drop table 表名;


資料庫誤刪除表之後恢復:(
絕對ok,我就做過這樣的事情,汗 )不過要記得刪除了哪些表名。
flashback table 表名 to before drop;

 

2.查詢得到當前資料庫中鎖,以及解鎖:

查鎖
SELECT /*+ rule */ s.username,
decode(l.type,'TM','TABLE LOCK',
'TX','ROW LOCK',
NULL) LOCK_LEVEL,
o.owner,o.object_name,o.object_type,
s.sid,s.serial#,s.terminal,s.machine,s.program,s.osuser
FROM v$session s,v$lock l,dba_objects o
WHERE l.sid = s.sid
AND l.id1 = o.object_id(+)
AND s.username is NOT NULL;

解鎖
alter system kill session 'sid,serial';
如果解不了。直接倒os下kill程式kill -9 spid

 

3.關於查詢資料庫使用者,許可權的相關語句:

 
1.檢視所有使用者:
select * from dba_user;
select * from all_users;
select * from user_users;


2.檢視使用者系統許可權:
select * from dba_sys_privs;
select * from all_sys_privs;
select * from user_sys_privs;


3.檢視使用者物件許可權:
select * from dba_tab_privs;
select * from all_tab_privs;
select * from user_tab_privs;


4.檢視所有角色:
select * from dba_roles;


5.檢視使用者所擁有的角色:
select * from dba_role_privs;
select * from user_role_privs;

 

4.幾個經常用到的oracle檢視:注意表名使用大寫....................

 
1. 查詢oracle中所有使用者資訊
       select  * from dba_user;
   2. 只查詢使用者和密碼
       select username,password from dba_users;
   3. 查詢當前使用者資訊
       select * from dba_ustats;
   4. 查詢使用者可以訪問的檢視文字
       select * from dba_varrays;
   5. 查詢資料庫中所有檢視的文字
       select * from dba_views;
6.查詢全部索引 
select * from user_indexes;
查詢全部表格
      select * from user_tables;
         查詢全部約束
      select * from user_constraints;
          查詢全部物件
      select * from user_objects;

 

5.檢視當前資料庫中正在執行的語句,然後可以繼續做很多很多事情,例如查詢執行計劃等等

 
(1).檢視相關程式在資料庫中的會話   
  Select   a.sid,a.serial#,a.program,   a.status   ,   
  substr(a.machine,1,20),   a.terminal,b.spid   
  from   v$session   a,   v$process   b   
  where   a.paddr=b.addr   
  and   b.spid   =   &spid;   
    
  (2).檢視資料庫中被鎖住的物件和相關會話   
  select   a.sid,a.serial#,a.username,a.program,   
  c.owner,   c.object_name     
  from   v$session   a,   v$locked_object   b,   all_objects   c   
  where   a.sid=b.session_id   and   
  c.object_id   =   b.object_id;   
    
  (3).檢視相關會話正在執行的SQL   
  select   sql_text   from   v$sqlarea   where   address   =     
  (   select   sql_address   from   v$session   where   sid   =   &sid   );   

 

6.查詢表的結構:表名大寫!!

select t.COLUMN_NAME,
       t.DATA_TYPE,
       nvl(t.DATA_PRECISION, t.DATA_LENGTH),
       nvl(T.DATA_SCALE, 0),
       c.comments
  from all_tab_columns t, user_col_comments c
 whEre t.TABLE_NAME = c.table_name
   and t.COLUMN_NAME = c.column_name
   and t.TABLE_NAME = UPPER('OM_EMPLOYEE_T')
 order by t.COLUMN_ID     

 

7.行列互換:

 
建立一個例子表:
CREATE TABLE t_col_row( 
ID INT, 
c1 VARCHAR2(10), 
c2 VARCHAR2(10), 
c3 VARCHAR2(10)); 
INSERT INTO t_col_row VALUES (1, 'v11', 'v21', 'v31'); 
INSERT INTO t_col_row VALUES (2, 'v12', 'v22', NULL); 
INSERT INTO t_col_row VALUES (3, 'v13', NULL, 'v33'); 
INSERT INTO t_col_row VALUES (4, NULL, 'v24', 'v34'); 
INSERT INTO t_col_row VALUES (5, 'v15', NULL, NULL); 
INSERT INTO t_col_row VALUES (6, NULL, NULL, 'v35'); 
INSERT INTO t_col_row VALUES (7, NULL, NULL, NULL); 
COMMIT; 

下面的是列轉行:建立了一個檢視
CREATE view v_row_col AS
SELECT id, 'c1' cn, c1 cv
FROM t_col_row
UNION ALL
SELECT id, 'c2' cn, c2 cv
FROM t_col_row
UNION ALL
SELECT id, 'c3' cn, c3 cv FROM t_col_row;

下面是建立了沒有空值的一個豎表:
CREATE view v_row_col_notnull AS
SELECT id, 'c1' cn, c1 cv
 FROM t_col_row 
where c1 is not null
UNION ALL
SELECT id, 'c2' cn, c2 cv
 FROM t_col_row
where c2 is not null
UNION ALL
SELECT id, 'c3' cn, c3 cv
 FROM t_col_row 
where c3 is not null;

  

8.下面可能是dba經常使用的oracle檢視吧。呵呵 

 
1.示例:已知hash_value:3111103299,查詢sql語句:
select * from v$sqltext 
where hashvalue='3111103299'
order by piece 
2.檢視消耗資源最多的SQL:
SELECT hash_value, executions, buffer_gets, disk_reads, parse_calls
FROM V$SQLAREA
WHERE buffer_gets > 10000000OR disk_reads > 1000000
ORDERBY buffer_gets + 100 * disk_reads DESC;

3.檢視某條SQL語句的資源消耗:
SELECT hash_value, buffer_gets, disk_reads, executions, parse_calls
FROM V$SQLAREA
WHERE hash_Value = 228801498AND address = hextoraw('CBD8E4B0');

4.查詢sql語句的動態執行計劃:
        首先使用下面的語句找到語句的在執行計劃中的address和hash_code
        SELECT sql_text, address, hash_value FROM v$sql t
                where (sql_text like '%FUNCTION_T(表名大寫!)%')
        然後:
        SELECT operation, options, object_name, cost FROM v$sql_plan
                WHERE address = 'C00000016BD6D248' AND hash_value = 664376056;

5.查詢oracle的版本:
select * from v$version;

6.查詢資料庫的一些引數:
select * from v$parameter

7.查詢你的session資訊
SELECT SID, OSUSER, USERNAME, MACHINE, PROCESS
FROM V$SESSION WHERE audsid = userenv('SESSIONID');

8.當machine已知的情況下查詢session
SELECT SID, OSUSER, USERNAME, MACHINE, TERMINAL
FROM V$SESSION
WHERE terminal = 'pts/tl' AND machine = 'rgmdbs1';

9.查詢當前被某個指定session正在執行的sql語句。假設sessionID為100
select b.sql_text 
from v$session a,v$sqlarea b 
where a.sql_hashvalue=b.hash_value and a.sid=100

 

9.樹形結構connect by 排序:

   
查詢樹形的資料結構,同時對一層裡面的資料進行排序
SELECT last_name, employee_id, manager_id, LEVEL
      FROM employees
      START WITH employee_id = 100
      CONNECT BY PRIOR employee_id = manager_id
      ORDER SIBLINGS BY last_name;



下面是查詢結果
LAST_NAME                 EMPLOYEE_ID MANAGER_ID      LEVEL
------------------------- ----------- ---------- ----------
King                              100                     1
Cambrault                         148        100          2
Bates                             172        148          3
Bloom                             169        148          3
Fox                               170        148          3
Kumar                             173        148          3
Ozer                              168        148          3
Smith                             171        148          3
De Haan                           102        100          2
Hunold                            103        102          3
Austin                            105        103          4
Ernst                             104        103          4
Lorentz                           107        103          4
Pataballa                         106        103          4
Errazuriz                         147        100          2
Ande                              166        147          3
Banda                             167        147          3
 

 

10.有時候寫多了東西,居然還忘記最基本的sql語法,下面全部寫出來,基本的oracle語句都在這裡可以找到了。是很基礎的語句!

1.在資料字典查詢約束的相關資訊:
SELECT constraint_name, constraint_type,search_condition
FROM        user_constraints WHERE        table_name = 'EMPLOYEES';
        //這裡的表名都是大寫!
2對錶結構進行說明:
   desc Tablename
3檢視使用者下面有哪些表
   select table_name from user_tables;
4檢視約束在那個列上建立:
   SELECT constraint_name, column_name
   FROM        user_cons_columns
   WHERE          table_name = 'EMPLOYEES';
10結合變數查詢相關某個表中約束的相關列名:
  select constraint_name,column_name from user_cons_columns where table_name = '&tablename'
12查詢資料字典看中間的元素:
SELECT   object_name, object_type
FROM     user_objects
WHERE    object_name LIKE 'EMP%'     
OR       object_name LIKE 'DEPT%'
14查詢物件型別:
SELECT DISTINCT object_type FROM           user_objects ;
17改變物件名:(表名,檢視,序列)
  rename  emp to emp_newTable
18新增表的註釋:
  COMMENT ON TABLE employees IS 'Employee Information';
20檢視檢視結構:
   describe view_name
23在資料字典中檢視檢視資訊:
  select viewe_name,text from user_views
25檢視資料字典中的序列:
  select * from user_sequences
33得到所有的時區名字資訊:
        select  * from v$timezone_names
34顯示對時區‘US/Eastern’的時區偏移量
        select TZ_OFFSET('US/Eastern') from DUAL--dual英文意思是‘雙重的’
   顯示當前會話時區中的當前日期和時間:
   ALTER SESSION SET NLS_DATE_FORMAT = 'DD-MON-YYYY HH24:MI:SS';--修改顯示時間的方式的設定
   ALTER SESSION SET TIME_ZONE = '-5:0';--修改時區
   SELECT SESSIONTIMEZONE, CURRENT_DATE FROM DUAL;--真正有用的語句!
  SELECT CURRENT_TIMESTAMP FROM DUAL;--返回的時間是當前日期和時間,含有時區
  SELECT CURRENT_TIMESTAMP FROM DUAL;--返回的時間是當前日期和時間,不含有時區!!!  
35顯示資料庫時區和會話時區的值:
        select datimezone,sessiontimezone from dual;

13普通的建表語句:
CREATE TABLE dept
(deptno         NUMBER(2),
dname         VARCHAR2(14),
loc         VARCHAR2(13));
15使用子查詢建立表:
 CREATE TABLE         dept80
  AS  SELECT  employee_id, last_name, 
            salary*12 ANNSAL, 
            hire_date   FROM    employees   WHERE   department_id = 80;
6新增列:// alter table EMP add column (dept_id number(7));錯誤!!
  alter table EMP add (dept_id number(7));
7刪除一列:
  alter table emp drop column dept_id;
8新增列名同時和約束:
 alter table EMP add (dept_id number(7) 
   constraint my_emp_dept_id_fk  references dept(ID));
9改變列://注意約束不能夠修改 的!!
 alter table dept80 modify(last_name varchar2(30));//這裡使用的是modify而不是alter!
24增加一行:
  insert into table_name values();

5新增主鍵:
 alter Table EMP  add constraint my_emp_id_pk primary key (ID);
11新增一個有check約束的新列:
  alter table EMP
  add (COMMISSION number(2) constraint emp_commission_ck check(commission>0))
16刪除表:
   drop table emp;
19建立檢視:
   CREATE VIEW         empvu80
 AS SELECT  employee_id, last_name, salary
    FROM    employees     WHERE   department_id = 80;
21刪除檢視:
   drop view view_name
22找到工資最高的5個人。(top-n分析)(行內檢視)
 select rownum,employee_id from (select employee_id,salary from
 employees order by salary desc)
  where rownum<5;
26建立同義詞:
  create synonym 同義詞名 for 原來的名字
或者  create public synonym 同義詞名 for 原來的名字
27建立序列:(注意,這裡並沒有出現說是哪個表裡面的序列!!)
  CREATE SEQUENCE dept_deptid_seq
                INCREMENT BY 10
                START WITH 120
                MAXVALUE 9999
                NOCACHE
                NOCYCLE  
28使用序列:
        insert into dept(ID,NAME) values(DEPT_ID_SEQ.nextval,'Administration');
29建立索引://預設就是nonunique索引,除非使用了關鍵字:unique
        CREATE INDEX emp_last_name_idx ON employees(last_name);
30建立使用者:(可能有錯,詳細檢視幫助)
        create user  username(使用者名稱)
        identified by oracle(密碼)
        default tablespace  data01(表空間名//預設存在system表空間裡面)
        quota 10M(設定大小,最大為unlimited)  on 表空間名//必須分配配額!
31建立角色:create ROLE manager
    賦予角色許可權:grant create table,create view to manage
    賦予使用者角色:grant manager to DENHAAN,KOCHHAR( 兩個使用者)
32分配許可權:
        GRANT  update (department_name, location_id)
        ON     departments
        TO     scott, manager;
    回收許可權
        REVOKE  select, insert
        ON      departments
        FROM    scott;
36從時間中提取年,月,日:使用函式extract
        select extract(year from sysdate) year,extract(month from sysdate),
extract(day from sysdate) from dual;
37使用函式得到數月之後的日期:to_yminterval(‘01-02’)表示加上1年2月,不能夠到天!!
        select hire_date,hire_date +to_yminterval('01-02') as hire_date_new from employees where department_id=20
    得到多少天之後的日期:直接日期加數字!
        select hire_date +3 from employees where department_id=20
38一般的時間函式:
        MONTHS_BETWEEN ('01-SEP-95','11-JAN-94')--兩個日期之間的月數,返回一個浮點數
        ADD_MONTHS ('11-JAN-94',6)--新增月數
          NEXT_DAY ('01-SEP-95','FRIDAY') --下一個星期五的日期
        LAST_DAY('01-FEB-95')--當月的最後一天!
        ROUND(SYSDATE,'MONTH')         --四捨五入月
        ROUND(SYSDATE ,'YEAR')       --四捨五入年
        TRUNC(SYSDATE ,'MONTH')        --階段月
         TRUNC(SYSDATE ,'YEAR')        --截斷年  
39 group語句:和高階的應用語句:
        SELECT   department_id, job_id, SUM(salary),  COUNT(employee_id) FROM     employees
                GROUP BY department_id, job_id ;
        使用having進行約束:
        1.group by rollup:對n列組合得到n+1種情況
        SELECT   department_id, job_id, SUM(salary)        FROM     employees  WHERE    department_id < 60 GROUP BY ROLLUP(department_id, job_id);
        2.group by cube:得到2的n次方種情況
        SELECT   department_id, job_id, SUM(salary) FROM     employees  WHERE    department_id < 60 GROUP BY CUBE (department_id, job_id) ;
        3.使用grouping得到一行中構成列的情況,只是返回1和0:是空的話就返回1,否則返回0(注意不要弄反了!)
        SELECT   department_id DEPTID, job_id JOB,  SUM(salary),    GROUPING(department_id) GRP_DEPT,    GROUPING(job_id) GRP_JOB
                FROM     employees WHERE    department_id < 50 GROUP BY ROLLUP(department_id, job_id);
        4.grouping sets:根據需要得到制定的組合情況
        SELECT   department_id, job_id, manager_id,avg(salary) FROM     employees GROUP BY GROUPING SETS ((department_id,job_id), (job_id,manager_id));
40from中使用子查詢:返回每個部門中大於改部門平均工資的與員工資訊
        SELECT  a.last_name, a.salary, a.department_id, b.salavg  FROM    employees a,--下面的地方就是子查詢了,主要返回的是一組資料!
         (SELECT   department_id, AVG(salary) salavg   FROM     employees  GROUP BY department_id) b
        WHERE   a.department_id = b.department_id
        AND     a.salary > b.salavg;
41exists語句的使用:
        SELECT employee_id, last_name, job_id, department_id
        FROM   employees outer--下面的 exists裡面的select選擇出來的是隨便的一個字元或者數字都可以
        WHERE  EXISTS ( SELECT 'X'   FROM   employees WHERE  manager_id =  outer.employee_id);
42厲害的with語句:
        WITH 
         dept_costs  AS (--定義了一個臨時的表
                   SELECT  d.department_name, SUM(e.salary) AS dept_total--其間定義了一個臨時的列dept_total
                   FROM    employees e, departments d
                   WHERE   e.department_id = d.department_id
                   GROUP BY d.department_name),/*注意這裡有逗號*/
        avg_cost    AS (
           SELECT SUM(dept_total)/COUNT(*) AS dept_avg
           FROM   dept_costs)--這裡的第二張臨時表裡面就引用了前面定義的臨時表和之間的列!
        SELECT *  FROM   dept_costs  WHERE  dept_total >  (SELECT dept_avg   FROM avg_cost) ORDER BY department_name;---最後的查詢語句中使用了前面的臨時表
43遍歷樹:
        SELECT employee_id, last_name, job_id, manager_id
        FROM   employees
        START  WITH  employee_id = 101
        CONNECT BY PRIOR manager_id = employee_id ;--自底向上的遍歷樹。

44.更新語句
UPDATE employees SET 
    job_id = 'SA_MAN', salary = salary + 1000, department_id = 120 
    WHERE first_name||' '||last_name = 'Douglas Grant'; 

UPDATE TABLE (SELECT projs 
           FROM dept d WHERE d.dno = 123)  p 
  SET p.budgets = p.budgets + 1 
  WHERE p.pno IN (123, 456);

 

11.匯入匯出dmp檔案:

imp 使用者名稱/密碼@資料庫 ignore=y file=備份檔案 log=D:\DBtest\db_bak\imp.log

 

exp system/manager@TEST file=d:\daochu.dmp full=y

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