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MySQL的几个问题

Java&Inter — Tue, 13 Jun 2006 07:43:00 GMT

    最近由于做一个小型的项目，用到了Mysql，遇到了一些问题，到网上google了一下，找到了一些解决的方法，希望对您有些帮助，呵呵。

1.       在安装Mysql之后，在service里面没有出现mysql的服务
        C:\mysql\bin\mysqld –install
        C:\mysql\bin\mysqld-nt –standalone （不想把 mysql 作为一个服务启动）

2.       当把 mysql 安装到 c 盘意外的地方的时候，启动 mysql 会报错： 1067

解决方案：
you seemed have your mysql installed in windows. so this problem may becaused if you're not installing mysql in c:\mysql.

you can simply copy all files to c:\mysql or
create a file call my.ini(store it in %windows%) OR my.cnf (store it in c:\) and the followingcontent should be in the file
assume you have mysql ind:\mysql

[mysqld]
#set basedir to the installationpath
basedir=d:/mysql
datadir=d:/mysql/data

note that the forward slashes (/) are being used.

Java&Inter 2006-06-13 15:43 发表评论

恼人的oracle xmldb--Oracle与Tomcat的端口冲突

Java&Inter — Thu, 17 Nov 2005 01:59:00 GMT

恼人的oracle xmldb,一装完oracle,默认xmldb就占了8080端口

1.使用sys登录Oracle，利用dbms_xdb修改端口设置

SQL> -- Change the HTTP/WEBDAV port from 8080 to 8081
SQL> call dbms_xdb.cfg_update(updateXML(
    2      dbms_xdb.cfg_get()
    3      , '/xdbconfig/sysconfig/protocolconfig/httpconfig/http-port/text()'
    4      , 8081))
    5 /

Call completed.

SQL> -- Change the FTP port from 2100 to 2111
SQL> call dbms_xdb.cfg_update(updateXML(
    2       dbms_xdb.cfg_get()
    3       , '/xdbconfig/sysconfig/protocolconfig/ftpconfig/ftp-port/text()'
    4       , 2111))
    5 /

Call completed.

SQL> COMMIT;

Commit complete.

SQL> EXEC dbms_xdb.cfg_refresh;

PL/SQL procedure successfully completed.

2.使用OEM console，选择数据库，XML Database，Configuration。更改XDB的有关设置。

3.去掉数据库的初始化参数： dispatchers='(PROTOCOL=TCP) (SERVICE=XDB)'，将会禁止XDB的http和ftp服务

4.呵呵,当然就是改变Tomcat的Port了哦

Java&Inter 2005-11-17 09:59 发表评论

Oracle数据库的Blob,LongRaw类型的访问

Java&Inter — Wed, 17 Aug 2005 05:13:00 GMT

在现在很多的应用中，数据库会经常要存取一些大容量的数据，典型的代表：Blob,LongRaw
本文主要介绍这两种类型存取图形的操作(jsp页面的访问)。

一 Blob
建立Table:

CREATE TABLE PHOTO
(
PHOTO_NO VARCHAR2(1) NOT NULL,
IMAGE BLOB
)

showimage.jsp

<%
  /*
    從Oracle數據庫中讀取Blob的類型,並且在jsp頁面中顯示出來
  */
%>
<%@ page contentType="text/html; charset=BIG5" %>
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*, javax.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.math.*"%>

<%
String photo_no = request.getParameter("photo_no");
//out.print(photo_no);

//Oracle連結
Class.forName("oracle.jdbc.driver.OracleDriver");
String url="jdbc:oracle:thin:@IP:1521:SID";
String userName="user";
String pwd="pwd";
Connection conn=DriverManager.getConnection(url,userName,pwd);

try{
Statement stmt = conn.createStatement();

String sql = " SELECT * FROM PHOTO WHERE photo_no = "+ photo_no;
ResultSet rs = stmt.executeQuery(sql);
if (rs.next()) {
Blob b = rs.getBlob("image");
long size = b.length();
//out.print(size);
byte[] bs = b.getBytes(1, (int)size);
response.setContentType("image/jpeg");
OutputStream outs = response.getOutputStream();
outs.write(bs);
outs.flush();
rs.close();
}
else {
rs.close();

}
}
finally{
conn.close();
}
%>

index.html

<HTML>
<HEAD>
<TITLE>图像测试TITLE>

HEAD>

<BODY>
<TABLE>
<TR>
<TD>图像测试TD>
TR>
<TR>
<TD><img src="showimage.jsp?photo_no=1">TD>
TR>
TABLE>

BODY>
HTML>

二 LongRaw
建立Table:

CREATE TABLE PHOTO_2
(
PHOTO_NO VARCHAR2(1) NOT NULL,
IMAGE LONG RAW
)

showimage.jsp

<%
  /*
    從Oracle數據庫中讀取LongRaw的類型,並且在jsp頁面中顯示出來
  */
%>
<%@ page contentType="text/html; charset=BIG5" %>
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*, javax.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.math.*"%>

<%
String photo_no = request.getParameter("photo_no");
out.print(photo_no);

//Oracle連結
Class.forName("oracle.jdbc.driver.OracleDriver");
String url="jdbc:oracle:thin:@IP:1521:SID";
String userName="user";
String pwd="pwd";
Connection conn=DriverManager.getConnection(url,userName,pwd);

try{
Statement stmt = conn.createStatement();

String sql = " SELECT * FROM PHOTO_2 WHERE photo_no = "+ photo_no;
ResultSet rs = stmt.executeQuery(sql);
if (rs.next()) {
byte bs[]=rs.getBytes("image");
response.setContentType("image/jpeg");
OutputStream outs = response.getOutputStream();
outs.write(bs);
outs.flush();
rs.close();
}
else {
rs.close();

}
}
finally{
conn.close();
}
%>

PS:这样的访问必须要保证这些Blog或LongRaw类型的字段中存储的是图片文件。

Java&Inter 2005-08-17 13:13 发表评论

Oracle中如何删除重复的纪录

Java&Inter — Fri, 12 Aug 2005 08:51:00 GMT

如何查找重复的纪录：

SELECT * FROM TABLE_NAME

WHERE ROWID!=(SELECT MAX(ROWID) FROM TABLE_NAME D

WHERE TABLE_NAME.COL1=D.COL1 AND TABLE_NAME.COL2=D.COL2);

如何删除重复记录？

DELETE FROM TABLE_NAME

WHERE ROWID!=(SELECT MAX(ROWID) FROM TABLE_NAME D

WHERE TABLE_NAME.COL1=D.COL1 AND TABLE_NAME.COL2=D.COL2)

Java&Inter 2005-08-12 16:51 发表评论