c 连接mysql

apt-get install libmysqlclient-dev

mysql 使用的是xampp 需要指定sock

源码：main.c

#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/mysql.h>  //我的机器上该文件在/usr/local/include/mysql下   //定义数据库操作的宏，也可以不定义留着后面直接写进代码 #define SELECT_QUERY "select username from test where userid = %d"   int main(int argc, char **argv) //char **argv 相当于 char *argv[] {     MYSQL mysql,*sock;    //定义数据库连接的句柄，它被用于几乎所有的MySQL函数     MYSQL_RES *res;       //查询结果集，结构类型     MYSQL_FIELD *fd ;     //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  qbuf[160];      //存放查询sql语句字符串          if (argc != 2) {  //检查输入参数         fprintf(stderr,"usage : mysql_select <userid>\n\n");         exit(1);     }          mysql_init(&mysql);     if (!(sock = mysql_real_connect(&mysql,"localhost","root","","test",3306, "/opt/lampp/var/mysql/mysql.sock" ,0))) {         fprintf(stderr,"Couldn't connect to engine!\n%s\n\n",mysql_error(&mysql));         perror("");         exit(1);     }          sprintf(qbuf,SELECT_QUERY,atoi(argv[1]));     if(mysql_query(sock,qbuf)) {         fprintf(stderr,"Query failed (%s)\n",mysql_error(sock));         exit(1);     }          if (!(res=mysql_store_result(sock))) {         fprintf(stderr,"Couldn't get result from %s\n", mysql_error(sock));         exit(1);     }          printf("number of fields returned: %d\n",mysql_num_fields(res));              while (row = mysql_fetch_row(res)) {         printf("Ther userid #%d 's username is: %s\n", atoi(argv[1]),(((row[0]==NULL)&&(!strlen(row[0]))) ? "NULL" : row[0])) ;          puts( "query ok !\n" ) ;      }           mysql_free_result(res);     mysql_close(sock);     exit(0);     return 0;   //. 为了兼容大部分的编译器加入此行 }

编译：

gcc -o mysql_select ./main.c -lmysqlclient

---

简单类封装

test.sql

mysql>use test;

mysql>source ~/test.sql;

DROP TABLE IF EXISTS `test`; /*!40101 SET @saved_cs_client     = @@character_set_client */; /*!40101 SET character_set_client = utf8 */; CREATE TABLE `test` (   `id` int(11) NOT NULL AUTO_INCREMENT,   `value` text,   PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1; /*!40101 SET character_set_client = @saved_cs_client */;  -- -- Dumping data for table `test` --  LOCK TABLES `test` WRITE; /*!40000 ALTER TABLE `test` DISABLE KEYS */; INSERT INTO `test` VALUES (1,'hxl'),(2,'sqlite'),(3,'test'),(4,'for'),(5,'linux'); /*!40000 ALTER TABLE `test` ENABLE KEYS */; UNLOCK TABLES; /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */; /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */; /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */; /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */; /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */; /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */; /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;  -- Dump completed on 2012-07-02 23:52:14

main.cc

#include    <cstdlib> #include    <fstream> #include    <iomanip>    #include    <iostream>  extern "C" {  #include        <mysql/mysql.h> #include        <string.h>  } using namespace std;  class MyDb {     private:         MYSQL mysql,*sock;    //定义数据库连接的句柄，它被用于几乎所有的MySQL函数         MYSQL_RES *res;       //查询结果集，结构类型         MYSQL_FIELD *fd ;     //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      public:         MyDb()         {             cout<<"nothing"<<endl;         }         MyDb(char *ip, char *user, char *passwd, char *db_name, int port, char *socket)         {             mysql_init(&mysql);             if (!(sock = mysql_real_connect(&mysql, ip, user, passwd, db_name, port, socket ,0))) {                 fprintf(stderr,"Couldn't connect to engine!\n%s\n\n",mysql_error(&mysql));                 perror("");                 exit(1);             }          }         ~MyDb()         {             mysql_free_result(res);             mysql_close(sock);               cout<<"connect destoryed"<<endl;         }         void  get(char *str)         {             if(mysql_query(sock,str)) {                 fprintf(stderr,"Query failed (%s)\n",mysql_error(sock));                 exit(1);             }              if (!(res=mysql_store_result(sock))) {                 fprintf(stderr,"Couldn't get result from %s\n", mysql_error(sock));                 exit(1);             }             printf("number of fields returned: %d\n",mysql_num_fields(res));              while (row = mysql_fetch_row(res)) {                 printf("Ther username is: %s\n",(((row[0]==NULL)&&(!strlen(row[0]))) ? "NULL" : row[0])) ;                  puts( "query ok !" ) ;              }           } };      int main ( int argc, char *argv[] ) {     MyDb test("localhost","root","","test", 3306,"/opt/lampp/var/mysql/mysql.sock");     test.get("select value from test where id = 1");     return EXIT_SUCCESS; }        // ----------  end of function main  ----------

编译：

g++ -g -o mysql_select ./mysql.cc -lmysqlclient

完