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服务器之家 - 编程语言 - C/C++ - C++连接mysql的方法(直接调用C-API)

C++连接mysql的方法(直接调用C-API)

2021-05-19 16:01C++教程网 C/C++

首先安装mysql,点完全安装,才能在在安装目录include找到相应的头文件,注意,是完全安装,需要的朋友可以参考下

我装的是5.1版本,需要的头文件有

C++连接mysql的方法(直接调用C-API)

把需要的文件添加进去,然后再把 libmysql.lib放到项目目录里,文件在mysql安装目录 lib 下面.

?
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#include "stdafx.h"
#include <iostream>
#include <winsock2.h>
#include "mysql.h"
//#pragma comment(lib, "ws2_32.lib")
#pragma comment(lib,"libmysql.lib")
using namespace std;
int main(int argc, char* argv[])
{
 
  mysql_library_init(NULL,0,0);
  MYSQL mysql;
  mysql_init(&mysql);
 
  if(0==mysql_options(&mysql,MYSQL_SET_CHARSET_NAME,"utf8"))//设置字符集
  {
    cout << "设置字符集成功\n\n" <<endl;
  }
 
  if(!mysql_real_connect(&mysql,"localhost","root","kwgkwg","test",0,NULL,CLIENT_MULTI_STATEMENTS))//连接数据库
  {
    cout << "not connect mysql" << endl;
  }else
  {
    cout << "welcome to mysql\n\n\n";
  }
 
  mysql_query(&mysql,"select * from demo1");     //执行SQL语句
  MYSQL_RES *result=mysql_store_result(&mysql);    //获取资源
  int rowcount=mysql_num_rows(result);        //获取记录数
  unsigned int fieldcount=mysql_num_fields(result);  //获取字段数
 
  //cout << rowcount << endl;
 
  MYSQL_FIELD *field=NULL;              //字段
  MYSQL_ROW row=NULL;             //记录
  while(row=mysql_fetch_row(result))
  {
    for(unsigned int i=0;i<fieldcount;i++)
    {
      field=mysql_fetch_field_direct(result,i);
      cout<<field->name<<":"<<row[i] <<"\n";
    }
  }
 
 
  mysql_free_result(result);
  mysql_close(&mysql);
  mysql_server_end();
  mysql_library_end();
   
  return 0;
}

C++访问 (直接调用C-API)

?
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#include <iostream>
#include <windows.h>
#include <mysql.h>
#include <string>
static const char host[32] = "localhost";
static const char user[32] = "test";
static const char passwd[32] = "passwd";
static const char db[32] = "test";
/**
mysql> select * from t;
+----+
| id |
+----+
| 1 |
+----+
1 row in set (0.00 sec)
mysql> delimiter //
mysql> create procedure get_t(in t1 int)
  -> begin
  -> select id from t where id=t1;
  -> end
  -> //
Query OK, 0 rows affected (0.05 sec)
mysql> call get_t(1);
  -> //
+----+
| id |
+----+
| 1 |
+----+
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
*/
void test_more_results(MYSQL* h)
{
  char str[512] = "insert into test_num values(101);insert into test_num values(122);commit;";
  int r = mysql_real_query(h, str, strlen(str));
  if (r)
  {
    const char * error = mysql_error(h);
    std::cout<<"*** Connection Error " << error << std::endl;
  }
  do
  {
    MYSQL_RES* res = mysql_store_result(h);
    mysql_free_result(res);
  }
  while ( (0 == mysql_next_result(h)) );
   
}
void test_proc_stmt(MYSQL* h)
{
  MYSQL* mysql_ = h;
  MYSQL_BIND     bind;
  MYSQL_BIND     obind[1];
  // test_more_results(mysql_);
  MYSQL_STMT *hStmt = mysql_stmt_init(mysql_);
  my_bool true_value= 1;
  mysql_stmt_attr_set(hStmt, STMT_ATTR_UPDATE_MAX_LENGTH, (void*) &true_value);  
  char sql[] = "call get_t(?)";
  //char sql[] = "select id from t where id=?";
  if (mysql_stmt_prepare(hStmt, sql, strlen(sql)))
  {
    std::cout<<__LINE__<<": stmt prepare error: "<< (mysql_stmt_error(hStmt))<<std::endl;
    mysql_stmt_reset(hStmt);
    if (mysql_stmt_prepare(hStmt, sql, strlen(sql)))
    {
      std::cout<<__LINE__<<": stmt prepare error: "<< (mysql_stmt_error(hStmt))<<std::endl;
      mysql_close(mysql_);
      exit( -1);
    }
  }
  int id = 1;
  unsigned long id_len = 0;
  memset(&bind, 0, sizeof(bind));
  bind.buffer_type = FIELD_TYPE_LONG;
  bind.buffer = (void*)&id;
  bind.is_unsigned = true;
  bind.length = &id_len;
  // bind[0].buffer_length = sizeof(id);
  // bind[0].is_null = 0;
   
  if (mysql_stmt_bind_param(hStmt,(MYSQL_BIND*)(&bind)) != 0)
  {
    std::cout<<__LINE__<<": stmt prepare error: "<< (mysql_stmt_error(hStmt))<<std::endl;
    mysql_close(mysql_);
    exit( -1);
  }
  if (mysql_stmt_execute(hStmt) != 0)
  {
    std::cout<<__LINE__<<": stmt prepare error: "<< (mysql_stmt_error(hStmt))<<std::endl;
    mysql_close(mysql_);
    exit( -1);
  }
  int t2;
  memset(obind, 0, sizeof(obind));
  obind[0].buffer_type= MYSQL_TYPE_LONG;
  obind[0].buffer= (char *)&t2;
  obind[0].buffer_length = sizeof(t2);
   
  if (mysql_stmt_bind_result(hStmt, (MYSQL_BIND*)&obind[0]) != 0)
  {
    std::cout<<__LINE__<<": stmt prepare error: "<< (mysql_stmt_error(hStmt))<<std::endl;
    mysql_close(mysql_);
    exit( -1);
  }
  if ( mysql_stmt_store_result(hStmt) != 0 )
  {
    std::cout<<__LINE__<<": stmt prepare error: "<< (mysql_stmt_error(hStmt))<<std::endl;
    mysql_close(mysql_);
    exit( -1);
  }
   
   
  int rows = mysql_stmt_num_rows(hStmt);
  for (int i=0; i<rows; i++)
  {
    if (mysql_stmt_fetch(hStmt) == 0)
    {
      std::cout<<"id = "<<t2<<std::endl;
    }
  }
  mysql_stmt_free_result(hStmt);
  mysql_stmt_close(hStmt);
}
//
// Just for demo only.
//
int main()
{
  MYSQL*       mysql_ = NULL;
  MYSQL_RES*     result_ = NULL;
  MYSQL_ROW      row_;
  mysql_ = mysql_init(mysql_);
  // if (mysql_real_connect(mysql_, host, user, passwd, db, 3306, NULL, CLIENT_MULTI_STATEMENTS) == NULL)
  if (mysql_real_connect(mysql_, host, user, passwd, db, 3306, NULL, CLIENT_MULTI_STATEMENTS) == NULL)
  {
    const char * error = mysql_error(mysql_);
    std::cout<<"*** Connection Error " << error << std::endl;
    return -1;
  }
  mysql_autocommit(mysql_, false);
  std::string encodeStr = "set names 'gbk'";
  mysql_real_query(mysql_, encodeStr.c_str(), encodeStr.size());
   
  /*
  const char* tmpTableName = "t"; // assume you are querying the table 't'
  char str[512];
  int cnt = 0;
  sprintf(str,"select count(*) as cnt from %s", tmpTableName);
  mysql_real_query(mysql_, str, strlen(str));
  result_ = mysql_store_result(mysql_);
  while (row_ = mysql_fetch_row(result_))
  {
    // get the field value
    if (row_[0])
    {
      std::cout<<"count = "<<row_[0]<<std::endl;
      // convert it into int
      cnt = atoi(row_[0]);
      std::cout<<"cnt value = "<<row_[0]<<std::endl;
    }
  }
  mysql_free_result(result_);
  test_more_results();
  */
  test_proc_stmt(mysql_);
   
  do
  {
    MYSQL_RES* res = mysql_store_result(mysql_);
    mysql_free_result(res);
  }
  while ( (0 == mysql_next_result(mysql_)) );
   
  test_proc_stmt(mysql_);
  mysql_close(mysql_);
  return 0;
}

这样就差不多了,大家可以根据需要选择。

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