轉自:http://www.iteye.com/topic/648858
轉載請注明出處: http://renjie120.iteye.com/
注意:資料庫版本是10g,不過大部分9i的也适用,閃回9i就沒有.
1.曾經不小心把開發庫的資料庫表全部删除,當時吓的要死。結果找到下面的語句恢複到了1個小時之前的資料!很簡單。
注意使用管理者登入系統:
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;
資料庫誤删除表之後恢複:( 絕對ok,我就做過這樣的事情,汗 )不過要記得删除了哪些表名。
flashback table 表名 to before drop;
2.查詢得到目前資料庫中鎖,以及解鎖:
查鎖
SELECT 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程序kill -9 spid
ORA-28000:賬戶被鎖定
因為密碼輸入錯誤多次使用者自動被鎖定.
解決辦法:alter user user_name account unlock;
3.關于查詢資料庫使用者,權限的相關語句:
Sql代碼

- 1.檢視所有使用者:
- select * from dba_user;
- select * from all_users;
- select * from user_users;
- 2.檢視使用者系統權限:
- select * from dba_sys_privs;
- select * from all_sys_privs;
- select * from user_sys_privs;
- 3.檢視使用者對象權限:
- 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視圖:注意表名使用大寫....................
Sql代碼

- 1. 查詢oracle中所有使用者資訊
- select * from dba_user;
- 2. 隻查詢使用者和密碼
- select username,password from dba_users;
- 3. 查詢目前使用者資訊
- select * from dba_ustats;
- 4. 查詢使用者可以通路的視圖文本
- select * from dba_varrays;
- 5. 查詢資料庫中所有視圖的文本
- 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;
- 查詢全部限制
- select * from user_constraints;
- 查詢全部對象
- select * from user_objects;
5.檢視目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
Sql代碼

- (1).檢視相關程序在資料庫中的會話
- 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對象和相關會話
- 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:
Sql代碼

- 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:建立了一個視圖
- 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視圖吧。呵呵
Sql代碼

- 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$SQLAREA
- WHERE hash_Value = 228801498AND address = hextoraw('CBD8E4B0');
- 4.查詢sql語句的動态執行計劃:
- 首先使用下面的語句找到語句的在執行計劃中的address和hash_code
- SELECT sql_text, address, hash_value FROM v$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.查詢資料庫的一些參數:
- select * from v$parameter
- 7.查找你的session資訊
- SELECT SID, OSUSER, USERNAME, MACHINE, PROCESS
- FROM V$SESSION WHERE audsid = userenv('SESSIONID');
- 8.當machine已知的情況下查找session
- SELECT SID, OSUSER, USERNAME, MACHINE, TERMINAL
- FROM V$SESSION
- WHERE terminal = 'pts/tl' AND machine = 'rgmdbs1';
- 9.查找目前被某個指定session正在運作的sql語句。假設sessionID為100
- select b.sql_text
- from v$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:
Sql代碼

- 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
- <span style="background-color: #ff0000;"> ORDER SIBLINGS BY last_name;</span>
- 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文法,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!
Sql代碼

- 1.在資料字典查詢限制的相關資訊:
- SELECT constraint_name, constraint_type,search_condition
- FROM user_constraints WHERE table_name = 'EMPLOYEES';
- //這裡的表名都是大寫!
- 2對表結構進行說明:
- desc Tablename
- 3檢視使用者下面有哪些表
- select table_name from user_tables;
- 4檢視限制在那個列上建立:
- SELECT constraint_name, column_name
- FROM user_cons_columns
- WHERE table_name = 'EMPLOYEES';
- 10結合變量查找相關某個表中限制的相關列名:
- 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查詢對象類型:
- SELECT DISTINCT object_type FROM user_objects ;
- 17改變對象名:(表名,視圖,序列)
- rename emp to emp_newTable
- 18添加表的注釋:
- COMMENT ON TABLE employees IS 'Employee Information';
- 20檢視視圖結構:
- describe view_name
- 23在資料字典中檢視視圖資訊:
- 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’
- 顯示目前會話時區中的目前日期和時間:
- 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;--傳回的時間是目前日期和時間,含有時區
- SELECT CURRENT_TIMESTAMP FROM DUAL;--傳回的時間是目前日期和時間,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添加列:// alter table EMP add column (dept_id number(7));錯誤!!
- alter table EMP add (dept_id number(7));
- 7删除一列:
- alter table emp drop column dept_id;
- 8添加列名同時和限制:
- alter table EMP add (dept_id number(7)
- constraint my_emp_dept_id_fk references dept(ID));
- 9改變列://注意限制不能夠修改 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添加主鍵:
- alter Table EMP add constraint my_emp_id_pk primary key (ID);
- 11添加一個有check限制的新列:
- alter table EMP
- add (COMMISSION number(2) constraint emp_commission_ck check(commission>0))
- 16删除表:
- drop table emp;
- 19建立視圖:
- CREATE VIEW empvu80
- AS SELECT employee_id, last_name, salary
- FROM employees WHERE department_id = 80;
- 21删除視圖:
- drop view view_name
- 22找到工資最高的5個人。(top-n分析)(行内視圖)
- 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,這裡并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)
- 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//必須配置設定配額!
- 31建立角色:create ROLE manager
- 賦予角色權限: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配置設定權限:
- GRANT update (department_name, location_id)
- ON departments
- TO scott, manager;
- 回收權限
- REVOKE select, insert
- ON departments
- FROM scott;
- 36從時間中提取年,月,日:使用函數extract
- select extract(year from sysdate) year,extract(month from sysdate),
- extract(day from sysdate) from dual;
- 37使用函數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
- 38一般的時間函數:
- MONTHS_BETWEEN ('01-SEP-95','11-JAN-94')--兩個日期之間的月數,傳回一個浮點數
- ADD_MONTHS ('11-JAN-94',6)--添加月數
- 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') --四舍五入月
- ROUND(SYSDATE ,'YEAR') --四舍五入年
- TRUNC(SYSDATE ,'MONTH') --階段月
- TRUNC(SYSDATE ,'YEAR') --截斷年
- 39 group語句:和進階的應用語句:
- SELECT department_id, job_id, SUM(salary), COUNT(employee_id) FROM employees
- GROUP BY department_id, job_id ;
- 使用having進行限制:
- 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,隻是傳回1和0:是空的話就傳回1,否則傳回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:傳回每個部門中大于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,主要傳回的是一組資料!
- (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選擇出來的是随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),
- 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周遊樹:
- SELECT employee_id, last_name, job_id, manager_id
- FROM employees
- START WITH employee_id = 101
- CONNECT BY PRIOR manager_id = employee_id ;--自底向上的周遊樹。
- 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.導入導出dmp檔案:
imp 使用者名/密碼@資料庫 ignore=y file=備份檔案 log=D:\DBtest\db_bak\imp.log
exp system/[email protected] file=d:\daochu.dmp full=y
12.大對象字段blob:檢視blob字段的大小:
select dbms_lob.getLength (字段名) from 表名 ;
13.下面收集的是有意思的sql語句,說不定正是你需要的:
Java代碼

- --建立一個隻允許在工作時間通路的視圖
- create or replace view newviewemp
- as
- select * from 表名
- where exists(select 1 from dual where sysdate >=
- to_date(to_char(sysdate, 'yyyy-mm-dd ') || '08:00:00', 'yyyy-mm-dd hh24:mi:ss')
- and sysdate <
- to_date(to_char(sysdate, 'yyyy-mm-dd ') || '18:00:00', 'yyyy-mm-dd hh24:mi:ss'))
14.存儲過程中執行ddl語句:
Create Or Replace Procedure My_Proc As
Sqlddl Varchar2(1000);
Begin
Sqlddl := 'create table MyTable(ID Number(5), Name Varchar2(20))';
Dbms_Output.Put_Line(Sqlddl);
Execute Immediate Sqlddl;
End;