C++连接mysql的方法(直接调用C-API)
本文讲解"C++连接mysql的方法(直接调用C-API)"，用于解决相关问题。
我装的是5.1版本，需要的头文件有
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.
#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)
#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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