在Mysql中用 LONGBLOB 类型存储二进制数据

最新推荐文章于 2023-03-11 15:48:22 发布

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本文介绍如何使用Mysql的LONGBLOB类型来存储大容量的二进制数据，包括一个实际的例子，展示了从文件读取到通过预处理语句插入数据库的全过程。

在Mysql中用 LONGBLOB 类型存储二进制数据

作者：天涯来源：中国自学编程网发布日期：1247011310

//需要设置为你自己的

//在DBMS中线要创建数据库test，table bintest，data字段数据类型用LONGBLOB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
//max_allowed_packet = 1024M

//#define host "localhost" //mysql server
//#define username "root"
//#define password "674800"
//#define database "test"
//int port = 3306;

// Mysql3.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"

#include <Winsock2.h>
#include <mysql.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#pragma comment(lib,"libmysql.lib")

#define INSERT_QUERY "INSERT INTO bintest(id, data) VALUES(NULL, ?)"

#define host "localhost" //mysql server
#define username "root"
#define password "674800"
#define database "test"
int port = 3306;

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;
}
void test()
{
MYSQL_BIND bind[1];
unsigned long length;

char* pos = NULL;
off_t size;
FILE* fp;

char* 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 ((pos = (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 ((fread(pos, 1, size, fp)) < 0) //读文件失败
{
perror("fread file" );
exit(1);
}

MYSQL *mysql = mysql_init(NULL); //mysql 初始化
if (!mysql)
return;
if (!mysql_real_connect(mysql,host,username,password,"test",port,NULL,0))//链接服务器
{
int ret = mysql_errno(mysql);
mysql_close(mysql);
return;
}

MYSQL_STMT *stmt = mysql_stmt_init(mysql);
if (!stmt)
{
fprintf(stderr, " mysql_stmt_init(), out of memory\n");
exit(0);
}
if (mysql_stmt_prepare(stmt, INSERT_QUERY, strlen(INSERT_QUERY)))
{
fprintf(stderr, "\n mysql_stmt_prepare(), INSERT failed");
fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
exit(0);
}
memset(bind, 0, sizeof(bind));
//bind[0].buffer_type= MYSQL_TYPE_STRING;
//bind[0].buffer_type = MYSQL_TYPE_LONG;
bind[0].buffer = pos;
//bind[0].buffer_type = MYSQL_TYPE_TINY;
bind[0].buffer_type = MYSQL_TYPE_BLOB;
bind[0].length= &length;
bind[0].is_null= 0;

/* Bind the buffers */
if (mysql_stmt_bind_param(stmt, bind))
{
fprintf(stderr, "\n param bind failed");
fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
exit(0);
}

int rc =0;
/* Supply data in chunks to server */
if (mysql_stmt_send_long_data(stmt,0, pos, size))
{
fprintf(stderr, "\n send_long_data failed");
fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
exit(0);
}

// pos += size;

/* Supply the next piece of data */
if (mysql_stmt_send_long_data(stmt,0, pos, size))
{
fprintf(stderr, "\n send_long_data failed");
fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
exit(0);
}

/* Now, execute the query */
if (mysql_stmt_execute(stmt))
{
fprintf(stderr, "\n mysql_stmt_execute failed");
fprintf(stderr, "\n %s", mysql_stmt_error(stmt));
exit(0);
}
}

int main()
{
test();
//sleep(1);
return 0;
}