c语言怎么连接mysql数据库 代码

//vc工具中添加E:\WAMP\BIN\MYSQL\MYSQL5.5.8\LIB 路径

//在工程设置-》链接》库模块中添加 libmysql.lib

#include <stdio.h>

#include <time.h>

#include <string.h>

#include <winsock.h>

#include "E:\wamp\bin\mysql\mysql5.5.8\include\mysql.h"

void main(){

MYSQL *conn

MYSQL_RES *res

MYSQL_ROW row

char *server ="localhost"

char *user ="root"

char *password=""

char *database="test"

char sql[1024]="select * from chinaren"

conn=mysql_init(NULL)

if(!mysql_real_connect(conn,server,user,password,database,0,NULL,0)){

fprintf(stderr,"%s\n",mysql_error(conn))

exit(1)

}

if(mysql_query(conn,sql)){

fprintf(stderr,"%s\n",mysql_error(conn))

exit(1)

}

res=mysql_use_result(conn)

while((row = mysql_fetch_row(res))!=NULL){

printf("%s\n",row[2])

}

mysql_free_result(res)

mysql_close(conn)

}

===============================

#if defined(_WIN32) || defined(_WIN64) //为了支持windows平台上的编译

#include <windows.h>

#endif

#include <stdio.h>

#include <stdlib.h>

#include "mysql.h"

//定义数据库 *** 作的宏，也可以不定义留着后面直接写进代码

#define SELECT_QUERY "show tables"

int main(int argc, char **argv) //char **argv 相当于 char *argv[]

{

MYSQL mysql,*handle //定义数据库连接的句柄，它被用于几乎所有的MySQL函数

MYSQL_RES *result //查询结果集，结构类型

MYSQL_FIELD *field//包含字段信息的结构

MYSQL_ROW row //存放一行查询结果的字符串数组

char querysql[160] //存放查询sql语句字符串

//初始化

mysql_init(&mysql)

//连接数据库

if (!(handle = mysql_real_connect(&mysql,"localhost","user","pwd","dbname",0,NULL,0))) {

fprintf(stderr,"Couldn't connect to engine!\n%s\n\n",mysql_error(&mysql))

}

sprintf(querysql,SELECT_QUERY,atoi(argv[1]))

//查询数据库

if(mysql_query(handle,querysql)) {

fprintf(stderr,"Query failed (%s)\n",mysql_error(handle))

}

//存储结果集

if (!(result=mysql_store_result(handle))) {

fprintf(stderr,"Couldn't get result from %s\n", mysql_error(handle))

}

printf("number of fields returned: %d\n",mysql_num_fields(result))

//读取结果集的内容

while (row = mysql_fetch_row(result)) {

printf("table: %s\n",(((row[0]==NULL)&&(!strlen(row[0]))) ? "NULL" : row[0]) )

}

//释放结果集

mysql_free_result(result)

//关闭数据库连接

mysql_close(handle)

system("PAUSE")

//为了兼容大部分的编译器加入此行

return 0

}

对于SQL Server数据库，

C++使用MFC库,主要有两种方法可以连接sql数据库

1.利用ADO连接:

#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")

//必须import这个dll,这个文件通常放在C:\Program Files\Common Files\System\ado路径下.

_ConnectionPtr m_ptrConnection//数据库连接对象

构造函数中添加如下语句

m_ptrConnection = NULL

::CoInitialize(NULL)

//连接数据库的主要代码

BOOL DataVisitor::ConnectDataBase(_bstr_t connectionStr)

{

/*

Added by stone. If IDOConnection has not been set up,then create one.

*/

if(m_ptrConnection == NULL)

{

HRESULT hr = m_ptrConnection.CreateInstance(__uuidof(Connection))

if (FAILED(hr))

{

return FALSE

}

else

{

_bstr_t strConnect = connectionStr

//"Provider=SQLOLEDBServer=(local)Database=navigationuid=sapwd=3277625"

m_ptrConnection->CursorLocation = adUseClient

m_ptrConnection->IsolationLevel = adXactReadCommitted

try

{

m_ptrConnection->Open(strConnect,"","",adModeUnknown)

return TRUE

}

catch (_com_error e)

{

// AfxMessageBox((char *)e.Description())

return FALSE

}

}

}

return TRUE

}

2. 利用ODBC连接

#include <afxdao.h>

CDaoDatabase *MyDataBase

BOOL MyDB_OperSqL::Open_MyDatabase(CString connstr)

{

try

{

if (MyDataBase == NULL)

{

MyDataBase = new CDaoDatabase()

}

MyDataBase->Open(NULL,0,0,connstr)

}

catch( CDaoException* e )

{

CString message = _T("MyDB_OperSqL 数据库异常: ")

message += e->m_pErrorInfo->m_strDescription

char info[400]

sprintf(info,message)

DispErrorMessage(info,__LINE__)

e->Delete( )

return FALSE

}

catch (CMemoryException *e)

{

DispErrorMessage("MyDB_OperSqL 内存异常!",__LINE__)

e->Delete( )

return FALSE

}

catch(...)

{

DispErrorMessage("MyDB_OperSqL 其它异常!",__LINE__)

return FALSE

}

return TRUE

}

这里的连接字符串connstr一般是如下内容

"ODBCDRIVER={SQL Server}SERVER=(local)DATABASE=yourDataBaseUID=yourIDPWD=yourPassword"

如果直接用Microsoft ADO Datebase Control控件的话，连接字串可以自己生成，在控件的属性里面找到拷贝就行，这种最简单

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