Oracle公司宣称在Linux下安装Oracle9i数据库至少要有512MB的内存和至少1GB或者两倍
内存大小的交换空间，对于系统内存大于2GB的服务器，交换空间可以介于2GB—4GB之间。
如果是为了在一台仅有256M内存的普通PC机上试用Oracle9i，在分配了1GB左右的交换空间的情况下，也可以正常运行Oracle数
据库。
要检查内存空间，登录进入Linux，在命令行方式（bash环境）下执行如下命令：
grep MemTotal /proc/meminfo
要检查交换空间，在命令行下执行如下命令：
grep SwapTotal /proc/meminfo
CentOS 5下安装Oracle 11g
首先需要的软件有：
1、 linux_11gR1_database.zip //可在Oracle的官方网站下载得到，有1.71GB够
大吧。
2、 别忘了准备一份Oracle的官方帮助文档，是最权威的。
3、 CentOS-5.2-i386-bin-DVD.iso //可在CentOS官方网站下载得到，有3.74GB超级大。
呵呵！� ......
1. create table people (age int, id int);
2. 创建数据文件PeopleDate.txt.
数据为：
20,1
30,2
3. 创建命令文件“LoadData.ctl”
内容为：
LOAD DATA
INFILE './PeopleDate.txt.'
INTO TABLE people
APPEND
FIELDS TERMINATED BY ',' (age, id)
4. 在命令行上执行：
sqlldr userid=DBName/DBPassWd control= ......
oracle and sqlsever 常用数学函数对比
数学函数
1.绝对值
S:select abs(-1) value
O:select abs(-1) value from dual
2.取整(大)
S:select ceiling(-1.001) value
O:select ceil(-1.001) value from dual
3.取整（小）
S:select floor(-1.001) value
O:select floor(-1.001) value from dual
4.取整（截取）
S:select cast(-1.002 as int) value
O:select trunc(-1.002) value from dual
5.四舍五入
S:select round(1.23456,4) value 1.23460
O:select round(1.23456,4) value from dual 1.2346
6.e为底的幂
S:select Exp(1) value 2.7182818284590451
O:select Exp(1) value from dual 2.71828182
7.取e为底的对数
S:select log(2.7182818284590451) value 1
O:select ln(2.7182818284590451) value from dual; 1
8.取10为底对数
S:select log10(10) value 1
O:select log(10,10) value from dual; 1
9.取平方
S:select SQUARE(4) value 16
O:select power(4,2) value from dual 16
10.取� ......
一个db类 类似于jdbc的驱动和链接配置
package com.assi;
import org.apache.log4j.jdbc.JDBCAppender;
public class DB extends JDBCAppender {
public DB(){
this.setDriver("oracle.jdbc.driver.OracleDriver");
this.setURL("jdbc:oracle:thin:@172.18.220.10:1521:orcl");
this.setUser("log");
this.setPassword("log");
}
}
具体写日志的类 //没有注释 代码比较简单
package com.assi;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
public class CataLogs extends DB {
private DateFormat df = new SimpleDat ......
This article shows how Oracle's Heterogeneous Services can be configured to allow a database to connect to a Microsoft Access database using standard databases links. The method described can be used to connect to MS-Access from about any platform - Unix/ Linux or Windows.
MS-Access 2003 and Oracle 10g Release 1 are used to illustrate the concepts. However, this procedure should work with Oracle 8i, 9i and 10g databases, as well as various versions of MS-Access.
Step 1: Prepare the MS-Access environment
If you do not have a MS-Access environment, start by installing the required software and create a test table.
Step 2: Define ODBC connectivity
Use the ODBC Administrator Utility to define a local System DSN that can be used to connect to the Access database (same machine). Ensure that the correct *.MDB database file is selected.
Step 3: Prepare the Oracle Environment
Install the Oracle Database Server software on the same machine where MS-Access is installed.
NOTE: It ......
可以用Spotlight软件对数据库的运行状态进行监控。
当出现session锁时，我们要及时进行处理.
1. 查看哪些session锁:
SQL语句：select 'alter system kill session '''||sid||','||serial#||''';' from v$session where sid in (select sid from v$lock where block = 1);
SQL> select 'alter system kill session '''||sid||','||serial#||''';' from v$session where sid in (select sid from v$lock where block = 1);
'ALTERSYSTEMKILLSESSION'''||SID||','||SERIAL#||''';'
--------------------------------------------------------------------------------
alter system kill session '132,731';
alter system kill session '275,15205';
alter system kill session '308,206';
alter system kill session '407,3510';
2. 查看session锁.
sql语句：select s.sid, q.sql_text from v$sqltext q, v$session s
where q.address = s.sql_address
and s.sid = &sid
order by piece;
SQL> select s.sid,q.sql_text from v$sqltext q, v$session s where q.address = s.sql_address and s.sid in (select sid from v$lock where b ......
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