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

注意使用管理員登錄系統：

select * from 表名 as of timestamp sysdate-1/12???//查詢兩個小時前的某表數據！既然兩小時以前的數據都得到了，繼續怎么做，知道了吧。。

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如果drop了表，怎么辦？？見下面：

drop table 表名;

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數據庫誤刪除表之后恢復,不過要記得刪除了哪些表名。

flashback table 表名 to before drop;

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2.查詢得到當前數據庫中鎖，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;

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解鎖

alter system kill session 'sid,serial';

如果解不了。直接倒os下kill進程kill －9 spid

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?ORA-28000:賬戶被鎖定

因為密碼輸入錯誤多次用戶自動被鎖定.

解決辦法:alter user user_name account unlock;

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3.關于查詢數據庫用戶，權限的相關語句：

?查看所有用戶：??

select * from dba_user;???

select * from all_users;???

select * from user_users;???

?

?

查看用戶系統權限：??

select * from dba_sys_privs;???

select * from all_sys_privs;???

10.select * from user_sys_privs;???

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?

查看用戶對象權限：??

select * from dba_tab_privs;???

select * from all_tab_privs;???

select * from user_tab_privs;???

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?

查看所有角色：??

20.select * from dba_roles;???

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?

查看用戶所擁有的角色：??

select * from dba_role_privs;???

select * from user_role_privs;??

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

?查詢oracle中所有用戶信息??

???????select??* from dba_user;??

????只查詢用戶和密碼??

???????select username,password from dba_users;??

????查詢當前用戶信息??

???????select * from dba_ustats;??

????查詢用戶可以訪問的視圖文本??

???????select * from dba_varrays;??

????查詢數據庫中所有視圖的文本??

??????select * from dba_views;??

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;??

??????????查詢全部對象??

??????select * from user_objects;?

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查看當前數據庫中正在執行的語句，然后可以繼續做很多很多事情，例如查詢執行計劃等等

(1).查看相關進程在數據庫中的會話?????

??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).查看數據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).查看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???);????

(1).查看相關進程在數據庫中的會話??

??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).查看數據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).查看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???);???

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?????

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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;????

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下面的是列轉行:創建了一個視圖??

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;???

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下面是創建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;??

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;???

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下面的是列轉行:創建了一個視圖??

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;??

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下面是創建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;?

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:創建了一個視圖

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;

下面是創建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;

下面可能是dba經常使用的oracle視圖吧。呵呵

Sql代碼??

示例：已知hash_value:3111103299，查詢sql語句：??

select * from v$sqltext????

where hashvalue='3111103299'??

order by piece????

查看消耗資源最多的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;???

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查看某條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');???

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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!)%')???

????????然后:??

????????SELECT operation, options, object_name, cost FROM v$sql_plan???

????????????????WHERE address = 'C00000016BD6D248' AND hash_value = 664376056;???

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查詢oracle的版本:??

select * from v$version;???

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查詢數據庫的一些參數:??

select * from v$parameter???

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查找你的session信息??

SELECT SID, OSUSER, USERNAME, MACHINE, PROCESS???

FROM V$SESSION WHERE audsid = userenv('SESSIONID');???

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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';???

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查找當前被某個指定session正在運行的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??

Sql代碼?

示例：已知hash_value:3111103299，查詢sql語句：??

select * from v$sqltext???

where hashvalue='3111103299'?

order by piece???

查看消耗資源最多的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;??

?

查看某條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');??

?

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!)%')??

????????然后:??

????????SELECT operation, options, object_name, cost FROM v$sql_plan??

????????????????WHERE address = 'C00000016BD6D248' AND hash_value = 664376056;??

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查詢oracle的版本:??

select * from v$version;??

?

查詢數據庫的一些參數:??

select * from v$parameter??

?

查找你的session信息??

SELECT SID, OSUSER, USERNAME, MACHINE, PROCESS??

FROM V$SESSION WHERE audsid = userenv('SESSIONID');??

?

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';??

?

查找當前被某個指定session正在運行的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?

示例：已知hash_value:3111103299，查詢sql語句：

select * from v$sqltext

where hashvalue='3111103299'

order by piece

查看消耗資源最多的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;

查看某條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');

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!)%')

????????然后:

????????SELECT operation, options, object_name, cost FROM v$sql_plan

????????????????WHERE address = 'C00000016BD6D248' AND hash_value = 664376056;

查詢oracle的版本:

select * from v$version;

查詢數據庫的一些參數:

select * from v$parameter

查找你的session信息

SELECT SID, OSUSER, USERNAME, MACHINE, PROCESS

FROM V$SESSION WHERE audsid = userenv('SESSIONID');

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';

查找當前被某個指定session正在運行的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

樹形結構connect by 排序：

Sql代碼??

查詢樹形的數據結構，同時對一層里面的數據進行排序??

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;???

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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??

??

Sql代碼?

查詢樹形的數據結構，同時對一層里面的數據進行排序??

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??

??

查詢樹形的數據結構，同時對一層里面的數據進行排序

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

?

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語句都在這里可以找到了。是很基礎的語句！

Sql代碼??

在數據字典查詢約束的相關信息：??

SELECT constraint_name, constraint_type,search_condition???

FROM????????user_constraints WHERE????????table_name = 'EMPLOYEES';???

????????//這里的表名都是大寫！??

2對表結構進行說明：??

???desc Tablename???

3查看用戶下面有哪些表??

???select table_name from user_tables;???

4查看約束在那個列上建立：??

???SELECT constraint_name, column_name???

???FROM????????user_cons_columns???

???WHERE??????????table_name = 'EMPLOYEES';???

10結合變量查找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查詢數據字典看中間的元素：??

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查看視圖結構：??

???describe view_name??

23在數據字典中查看視圖信息：??

??select viewe_name,text from user_views???

25查看數據字典中的序列：??

??select * from user_sequences???

33得到所有的時區名字信息：??

????????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置???

???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顯示數據庫時區和會話時區的值：??

????????select datimezone,sessiontimezone from dual;???

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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刪除一列：??

??alter table emp drop column dept_id;???

8添加列名同時和約束：??

?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));//這里使用的是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創建視圖：??

???CREATE VIEW?????????empvu80???

?AS SELECT??employee_id, last_name, salary???

????FROM????employees?????WHERE???department_id = 80;???

21刪除視圖：??

???drop view view_name???

22找到工資最高的5個人。（top-n分析）（行內視圖）???

?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，這里并沒有出現說是哪個表里面的序列！！）??

??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：//默認就是nonunique索引，除非使用了關鍵字：unique??

????????CREATE INDEX emp_last_name_idx ON employees(last_name);???

30建立用戶：（可能有錯，詳細查看幫助）??

????????create user??username(用戶名)???

????????identified by oracle(密碼)???

????????default tablespace??data01(表空間名//默認存在system表空間里面)???

????????q

總結

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