Linux 下C语言连接mysql实例详解

  sudo apt-get install libmysqlclient-dev  

  mysql> show databases;  +--------------------+  | Database      |  +--------------------+  | information_schema |  | chat_room     |  | mysql       |  | mysql_shiyan    |  | performance_schema |  | sys        |  +--------------------+  6 rows in set (0.00 sec)  mysql> use chat_room;  Reading table information for completion of table and column names  You can turn off this feature to get a quicker startup with -A    Database changed  mysql> show tables;  +---------------------+  | Tables_in_chat_room |  +---------------------+  | user_message    |  +---------------------+  1 row in set (0.00 sec)  mysql> select * from user_message;  +------+-------+--------+  | ID  | name | passwd |  +------+-------+--------+  |  1 | linux | linux |  |  2 | lyt  | lyt  |  +------+-------+--------+  2 rows in set (0.00 sec)    

  #include<stdio.h>  #include<stdlib.h>  #include<errno.h>  #include<mysql/mysql.h>    int main(void)  {    char *sql;    sql="SELECT * FROM user_message;";    int res;//执行sql语句后的返回标志    MYSQL_RES *res_ptr;//指向查询结果的指针    MYSQL_FIELD *field;//字段结构指针    MYSQL_ROW result_row;//按行返回查询信息    int row,column;//查询返回的行数和列数    MYSQL *conn;//一个数据库链接指针    int i,j;      //初始化连接句柄    conn = mysql_init(NULL);      if(conn == NULL) { //如果返回NULL说明初始化失败      printf("mysql_init failed!n");      return EXIT_FAILURE;    }      //进行实际连接    //参数　conn连接句柄，host　mysql所在的主机或地址,user用户名,passwd密码,database_name数据库名,后面的都是默认    conn = mysql_real_connect(conn,"localhost","lyt","","chat_room",0,NULL,0);    if (conn) {      printf("Connection success!n");    } else {      printf("Connection failed!n");    }    mysql_query(conn,"set names gbk");//防止乱码。设置和数据库的编码一致就不会乱码      res = mysql_query(conn,sql);//正确返回0    if(res) {      perror("my_query");      mysql_close(conn);      exit(0);    } else{      //把查询结果给res_ptr      res_ptr = mysql_store_result(conn);      //如果结果不为空,则输出      if(res_ptr) {        column = mysql_num_fields(res_ptr);        row = mysql_num_rows(res_ptr);        printf("查到%d行n",row);        //输出结果的字段名        for(i = 0;field = mysql_fetch_field(res_ptr);i++) {          printf("%10s",field->name);        }        puts("");        //按行输出结果        for(i = 1;i < row+1;i++){          result_row = mysql_fetch_row(res_ptr);          for(j = 0;j< column;j++) {            printf("%10s",result_row[j]);          }          puts("");        }      }    }    //退出前关闭连接    mysql_close(conn);      return 0;  }    

  gcc -o mysql a.c -L/usr/lib/mysql -lmysqlclient  ./mysql   Connection success!  查到2行      ID   name  passwd       1   linux   linux       2    lyt    lyt