近日一项目遇到需要在DB中存储2进制数据流类型文件的问题，发现常用的mysql API都用不了，再研究，方知有一套专门的API来干这种数据，功能相当强大的说。
以下即为范例代码 --- 按照说明编译即可用，稍加修改即可存储2进制文件
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/*
mysql数据库存储二进制数据 linux
用途: 用 mysql_stmt_send_long_data()来向blob字段写入2进制数据流.
注意点：需要注意的是bind结构的buffer_type字段，必须与要输入的数据类型相符，
如：只写入一个long 数据，则用MYSQL_TYPE_LONG，写入字符流，用MYSQL_TYPE_STRING,
写入2进制数据流，用MYSQL_TYPE_BLOB
具体这个参数各字段的含义参见 mysql5.0手册
Compile: g++ -I/usr/include/mysql -L/usr/lib/mysql -lmysqlclient mysql_test.cpp
准备工作:
create database test;
use test;
CREATE TABLE `bintest` (
`id` int(11) NOT NULL default '0',
`data` blob
) ENGINE=MyISAM;
*/
#include <mysql.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#define INSERT_QUERY "INSERT INTO bintest(id, data) VALUES(4, ?)"
void test()
{
MYSQL_BIND bind[1];
unsigned long length;
char blog_data[100] = {0};
memset(blog_data, 0x01, sizeof(blog_data));
char* pos = blog_data;
int size = 50;
MYSQL *mysql = mysql_init(NULL);
if (!mysql) return;
if (!mysql_real_connect(mysql,
"192.168.xx.xxx",
"root",
"db_user_name",
"test",
3306, NULL, 0))
{
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 = blog_data;
//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;
}
