MySql2.cpp : Defines the entry point for the console application.
#include "stdafx.h"//是前一篇的姊妹篇
//代码来自网络,我学习整理了一下,测试通过,下面的参数
//需要设置为你自己的
//在DBMS中线要创建数据库www,table www,file字段数据类型用LONGTEXT即可测试
//测试文件c:\\test.iso,你可以找任何一个文件修改为即可,我找的是一个exe程序,修改为test.iso而已
//最大测试过加入文件大小为650M(一个正真的iso文件)
//注意:还要修改my.ini文件中的max_allowed_packet字段,我设置的是
代码如下:
//max_allowed_packet = 1024M
//#define host "localhost" //mysql server
//#define username "root"
//#define password "674800"
//#define database "test"
//int port = 3306;
#include
#include
#include
#include
#include
#include
#include
#define host "localhost" //mysql server
#define username "root"
#define password "674800"
#define database "www"
int port = 3306;
#pragma comment(lib,"libmysql.lib")
//得到文件的大小(字节数)
int get_file_size(char *path, off_t *size)
{
struct stat file_stats;
if(stat(path, &file_stats))
return -1;
*size = file_stats.st_size;
return 0;
}
int main(int argc, char *argv[])
{
char *filename=NULL;
off_t size;
MYSQL *conn=NULL;
MYSQL_RES *res_set=NULL;
MYSQL_ROW row;
MYSQL_FIELD *field=NULL;
int i, flag;
char *sql; //sql语句
FILE *fp;
char *buf;
int n=256;
char *end;
unsigned long *length;
/* if (argc != 2)
{
printf("Usage: %s srcfile\n", argv[0]);
exit(1);
}
*/
filename = "c:\\test.iso";
if ((get_file_size(filename, &size)) == -1) //得到文件的大小
{
perror("get file size" );
exit(1);
}
if ((buf = (char *)malloc(sizeof(char)*(size+1))) == NULL)
{
perror("malloc buf" );
exit(1);
}
if ((fp = fopen(filename, "rb" )) == NULL) //读文件
{
perror("fopen file" );
exit(1);
}
if ((n = fread(buf, 1, size, fp)) {
perror("fread file" );
exit(1);
}
sql = (char *)malloc(sizeof(char)*n*2+256); //2n+1+strlen(other sql)
if (sql == NULL)
{
perror("malloc sql" );
exit(1);
}
conn = mysql_init(NULL);//生产一个mysql对象
if (conn == NULL)
{
printf("init mysql, %s\n", mysql_error(conn));
exit(1);
}
if ((mysql_real_connect(conn, host, username, password, database, port, NULL, 0)) == NULL) //连接服务器
{
printf("connect mysql, %s\n", mysql_error(conn));
exit(1);
}
strcpy(sql, "insert into www(id, name, file) values(NULL, 'peter', " );
end = sql;
end += strlen(sql); //point sql tail
//convert NUL(ASCII 0)、'\n'、'\r'、'\''、'''、'"'和Control-Z and so on
*end++ = '\'';
end += mysql_real_escape_string(conn, end, buf, n);
*end++ = '\'';
*end++ = ')';
flag = mysql_real_query(conn, sql, (unsigned int)(end-sql));
if (flag != 0)
{
printf("insert failed, %s\n", mysql_error(conn));
exit(1);
}
if ((mysql_real_query(conn, "SELECT file FROM www where id=1", 31)) != 0)
{
printf("insert failed, %s\n", mysql_error(conn));
exit(1);
}
res_set = mysql_store_result(conn);
fclose(fp);
fp = NULL;
fp = fopen("c:\\123.iso", "wb" );
while ((row = mysql_fetch_row(res_set)) != NULL)
{
length = mysql_fetch_lengths(res_set);
for (i=0; i
fwrite(row[0], 1, length[0], fp);
//printf("%s\n",row[0]);
}
}
fclose(fp);
mysql_close(conn);
free(sql);
free(buf);
sql = NULL;
return 0;
}
运行结果:

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了关于架构原理的相关内容,MySQL Server架构自顶向下大致可以分网络连接层、服务层、存储引擎层和系统文件层,下面一起来看一下,希望对大家有帮助。

mysql的msi与zip版本的区别:1、zip包含的安装程序是一种主动安装,而msi包含的是被installer所用的安装文件以提交请求的方式安装;2、zip是一种数据压缩和文档存储的文件格式,msi是微软格式的安装包。

方法:1、利用right函数,语法为“update 表名 set 指定字段 = right(指定字段, length(指定字段)-1)...”;2、利用substring函数,语法为“select substring(指定字段,2)..”。

在mysql中,可以利用char()和REPLACE()函数来替换换行符;REPLACE()函数可以用新字符串替换列中的换行符,而换行符可使用“char(13)”来表示,语法为“replace(字段名,char(13),'新字符串') ”。

转换方法:1、利用cast函数,语法“select * from 表名 order by cast(字段名 as SIGNED)”;2、利用“select * from 表名 order by CONVERT(字段名,SIGNED)”语句。

本篇文章给大家带来了关于mysql的相关知识,其中主要介绍了关于MySQL复制技术的相关问题,包括了异步复制、半同步复制等等内容,下面一起来看一下,希望对大家有帮助。

在mysql中,可以利用REGEXP运算符判断数据是否是数字类型,语法为“String REGEXP '[^0-9.]'”;该运算符是正则表达式的缩写,若数据字符中含有数字时,返回的结果是true,反之返回的结果是false。

在mysql中,是否需要commit取决于存储引擎:1、若是不支持事务的存储引擎,如myisam,则不需要使用commit;2、若是支持事务的存储引擎,如innodb,则需要知道事务是否自动提交,因此需要使用commit。


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