oracle中常见ck和fk是什么,Oracle常用知识总结
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。。
如果drop了表，怎么辦？？見下面：
drop table 表名;
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;
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;
解鎖
alter system kill session
'sid,serial';
如果解不了。直接倒os下kill進程kill －9 spid
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;
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;
查看用戶對象權限：
select * from
dba_tab_privs;
select * from
all_tab_privs;
select * from
user_tab_privs;
查看所有角色：
20.select * from
dba_roles;
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;
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
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: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;
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: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;
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;
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$sqlarea
b
where a.sql_hashvalue=b.hash_value and
a.sid=100
Sql代碼
示例：已知hash_value:3111103299，查詢sql語句：
select * from
v$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;
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;
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;
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
來源：
總結
以上是生活随笔為你收集整理的oracle中常见ck和fk是什么,Oracle常用知识总结的全部內容，希望文章能夠幫你解決所遇到的問題。
- 上一篇： oracle rac 错误日志路径,OR
- 下一篇： oracle_j000,ORA-600[