怎么用c++调用writefile与鼠标驱动交互

发布网友发布时间：2022-04-12 21:54

共2个回答

懂视网时间：2022-04-13 02:15

MySQL database does support C program API just like PHP or perl.

The C API code is distributed with MySQL. It is included in the mysqlclient library and allows C programs to access a database.

Many of the clients in the MySQL source distribution are written in C. If you are looking for examples that demonstrate how to use the C API, take a look at these clients. You can find these in the clients directory in the MySQL source distribution.

Requirements

Make sure you have development environment installed such as gcc, mysql development package etc. Following is the list summarize the list of packages to compile program:

mysql: MySQL client programs and shared library

mysqlclient: Backlevel MySQL shared libraries (old libs)

mysql-devel: Files for development of MySQL applications (a must have)

mysql-server: Mysql server itself

gcc, make and other development libs: GNU C compiler

Sample C Program

Following instructions should work on any Linux distro or UNIX computer. Here is the small program that connects to mysql server and list tables from mysql database.(download link):

* Simple C program that connects to MySQL Database server*/ #include <mysql.h> #include <stdio.h> main() { MYSQL *conn; MYSQL_RES *res; MYSQL_ROW row; char *server = "localhost"; char *user = "root"; char *password = "PASSWORD"; /* set me first */ char *database = "mysql"; conn = mysql_init(NULL); /* Connect to database */ if (!mysql_real_connect(conn, server, user, password, database, 0, NULL, 0)) { fprintf(stderr, "%s/n", mysql_error(conn)); exit(1); } /* send SQL query */ if (mysql_query(conn, "show tables")) { fprintf(stderr, "%s/n", mysql_error(conn)); exit(1); } res = mysql_use_result(conn); /* output table name */ printf("MySQL Tables in mysql database:/n"); while ((row = mysql_fetch_row(res)) != NULL) printf("%s /n", row[0]); /* close connection */ mysql_free_result(res); mysql_close(conn); }

How do I compile and link program against MySQL libs?

MySQL comes with a special script called mysql_config. It provides you with useful information for compiling your MySQL client and connecting it to MySQL database server. You need to use following two options.
Pass --libs option - Libraries and options required to link with the MySQL client library.

$ mysql_config --libs
Output:

-L/usr/lib64/mysql -lmysqlclient -lz -lcrypt -lnsl -lm -L/usr/lib64 -lssl -lcrypto

Pass --cflags option - Compiler flags to find include files and critical compiler flags and defines used when compiling the libmysqlclient library.
$ mysql_config --cflags
Output:

-I/usr/include/mysql -g -pipe -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing

You need to pass above option to GNU C compiler i.e. gcc. So to compile above program, enter:
$ gcc -o output-file $(mysql_config --cflags)mysql-c-api.c $(mysql_config --libs)
Now execute program:
$ ./output-file
Output:

MySQL Tables in mysql database:


columns_priv


db


func


help_category


help_keyword


help_relation


help_topic


host


tables_priv


time_zone


time_zone_leap_second


time_zone_name


time_zone_transition


time_zone_transition_type


user

References:

MySQL C API - A must read - official MySQL C API documentation

热心网友时间：2022-04-12 23:23

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
#include
#include
#include 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);
}
}