怎样在C++中调用MYSQL数据库中的数据

1、用CAPI连接MySQL数据库有两个步骤：

1）初始化一个连接句柄

2）建立连接

所用到的函数如下：

MYSQL *mysql_init(MYSQL *connection) // 初始化连接句柄

//成功返回MySQL结构指针，失败返回NULL

MYSQL *mysql_real_connect(MYSQL *connection,

const char *server_host,

const char *sql_user_name,

const char *sql_password,

const char *db_name,

unsigned int port_number,

const char *unix_socket_name,

unsigned int flags) //建立连接

//成功返回MySQL结构指针，失败返回NULL

以下是完整实例：

#include <iostream>

#include <fstream>

#include <cstdlib>

#include <mysql/mysql.h>

using namespace std

void mysql_err_function(MYSQL * connection)

int main()

{

//freopen("input.txt","r",stdin)

MYSQL * connection

connection = mysql_init(NULL)

if (!connection)

{

cout <<"mysql_init failed!" <<endl

exit(-1)

}

if (!mysql_real_connect(connection,"localhost","root","123456","test",0,NULL,0))

{

cout <<"Connection To MySQL failed!" <<endl

mysql_err_function(connection)

}

cout <<"Connection To MySQL Server is Success..." <<endl

string str

getline(cin,str)

int res = 0

int affected_count = 0

while (str != "close" &&str != "" &&!res)

{

res = mysql_query(connection,str.c_str())

affected_count += mysql_affected_rows(connection)

if (res)

{

if (mysql_errno(connection))

{

cout <<"Error " <<mysql_errno(connection) <<" : "

<<mysql_error(connection) <<'\n' <<endl

break

}

}

getline(cin,str)

}

cout <<"Have affected " <<affected_count <<" rows!" <<endl

mysql_close(connection)

cout <<"Connection To MySQL Server is closed..." <<endl

return 0

}

void mysql_err_function(MYSQL * connection)

{

if (mysql_errno(connection))

{

cout <<"Error " <<mysql_errno(connection) <<" : "

<<mysql_error(connection) <<endl

exit(-1)

}

}

1、方法一：重命名所有的表，代码如下:

CREATE

DATABASE

new_db_name

RENAME

TABLE

db_name.table1

TO

new_db_name.table1,

db_name.table2

TO

new_db_name.table2

DROP

DATABASE

db_name

2、方法二：mysqldump导出数据再导入，代码如下:

mysqldump

-uxxxx

-pxxxx

-h

xxxx

db_name

>

db_name_dump.SQL

mysql

-uxxxx

-pxxxx

-h

xxxx

-e

“CREATE

DATABASE

new_db_name”

mysql

-uxxxx

-pxxxx

-h

xxxx

new_db_name

<

db_name_dump.SQL

mysql

-uxxxx

-pxxxx

-h

xxxx

-e

“DROP

DATABASE

db_name”

3、方法三：使用shell脚本重命名所有的表，代码如下:

#!/bin/bash

mysqlconn=”mysql

-u

xxxx

-pxxxx

-S

/var/lib/mysql/mysql.sock

-h

localhost”

olddb=”db_name”

newdb=”new_db_name”

#$mysqlconn

-e

“CREATE

DATABASE

$newdb”

params=$($mysqlconn

-N

-e

“SELECT

TABLE_NAME

FROM

INFORMATION_SCHEMA.TABLES

WHERE

table_schema='$olddb'”)

for

name

in

$params

do

$mysqlconn

-e

“RENAME

TABLE

$olddb.$name

to

$newdb.$name”

done

#$mysqlconn

-e

“DROP

DATABASE

$olddb”

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