Linux下sqlite3编程

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交叉编译器：arm-linux-gcc-4.5.4

Linux内核版本：Linux-3.0

主机操作系统：Centos 6.5

开发板：FL2440

温度传感器:ds18b20

注：此程序的客户端是在装有ds18b20模块并有ds18b20驱动的系统上跑的，本人写的ds18b20的驱动

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以下操作是建立在你有sqlite3数据库的情况下，sqlite3数据库的安装参考链接：http://www.linuxidc.com/Linux/2012-07/66854.htm

注：数据库安装好之后会在/home下自动创建一个sqlite-3.6.18的用户，其中保存了数据库sqlite3所有的执行文件，头文件还有库函数。

以下程序实现的功能是：客户端读取温度传感器的温度以及当时的时间，并向服务器发送数据。若连接服务器失败则保存数据到数据库。等待客户端可以连接上服务器的时候把保存的数据发送给服务器。

一、客户端代码

 /*********************************************************************************
  *      Copyright:  (C) 2016 2013dianxin_3
  *                  All rights reserved.
  *
  *       Filename:  mclient.c
  *    Description:  This file
  *
  *        Version:  1.0.0(08/16/2016)
  *         Author:  xiaohexiansheng <1392195453@qq.com>
  *      ChangeLog:  1, Release initial version on "08/16/2016 07:16:44 PM"
  *
  ********************************************************************************/
 #include <sys/types.h>
 #include <sys/ioctl.h>
 #include <termios.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <sys/time.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <sqlite3.h>

 #define MAXLINE                 4096
 char                            get_sql[];
 /********************************************************************************
  *  Description:
  *   Input Args:
  *  Output Args:
  * Return Value:
  ********************************************************************************/
 double get_tem(void)        //获取温度的函数
 {
     int fd;
     double result = ;
     unsigned char buff[];
     unsigned short temp = ;
     int flag = ;

     if ((fd=open("/dev/ds18b20",O_RDWR | O_NDELAY | O_NOCTTY)) < )
     {
         perror("open device ds18b20 failed.\r\n");
         exit();
     }

     printf("open device ds18b20 success.\r\n");

     read(fd, buff, sizeof(buff));
     temp=((unsigned short)buff[])<<;
     temp|=(unsigned short)buff[];
     result=0.0625*((double)temp);
     close(fd);
     printf("temperature is %4f \r\n", result);
     return result;
 }

 int save_tem(char *s_temp)            //将数据保存到数据库
 {
     char sql[];
     sqlite3 *db;
     FILE *fd;

     sqlite3_open("temperature.db", &db);
     memset(sql, '\0', );
     strcpy(sql, "create table tb(id INTEGER PRIMARY KEY, data TEXT)");
     sqlite3_exec(db, sql, NULL, NULL, NULL);

     memset(sql, '\0', );
     strcpy(sql, "insert into tb(data) values(\"");
     strcat(sql, s_temp);
     strcat(sql, "\")");
     sqlite3_exec(db, sql, NULL, NULL, NULL);
     sqlite3_close(db);
     return ;
 }

 int wf_callback(void *addr, int nr, char **values, char **names)        //回掉函数依次将数据库中的数据发送给服务器
 {

     int         sockfd;
     char        sendline[MAXLINE];
     struct sockaddr_in servaddr;

     if((sockfd = socket(AF_INET, SOCK_STREAM, )) < )
     {
         printf("create socket error: %s(errno: %d).\n", strerror(errno), errno);
         return ;
     }

     memset(&servaddr, , sizeof(servaddr));
     servaddr.sin_family = AF_INET;
     servaddr.sin_port = htons();
     if(inet_pton(AF_INET, addr, &servaddr.sin_addr) <= )
     {
         printf("inet_pton error for %s.\n", addr);
         return ;
     }

     memset(sendline, , sizeof(sendline));
     if(connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < )
     {
         printf("connect error: %s(errno: %d)\n", strerror(errno), errno);
         return ;
     }

     if(send(sockfd, values[], strlen(values[]), ) < )
     {
         printf("send msg error: %s(errno: %d)\n", strerror(errno), errno);
         return ;
     }
     close(sockfd);
     return ;
 }

 int read_sql(char *addr)        //读取数据库中的数据并发送的函数
 {
     char sql[];
     sqlite3 *db;

     sqlite3_open("test.db", &db);
     sqlite3_exec(db, "select * from tb", wf_callback, addr, NULL);        //读取数据，并调用回调函数

     sqlite3_close(db);
     return ;
 }

 int delet_sql(void)                //删除数据库中表的函数
 {
     char sql[];
     sqlite3 *db;

     sqlite3_open("test.db", &db);
     sqlite3_exec(db, "DROP TABLE tb;", NULL, NULL, NULL);

     sqlite3_close(db);
     return ;
 }

 int main (int argc, char **argv)
 {
     double      temperature;
     int         sockfd;
     int         ret;
     char        timE[];
     time_t      rawtime;
     char        temp[];
     char        sendline[MAXLINE];
     char        recvline[MAXLINE];
     struct tm* timeinfo;
     struct sockaddr_in servaddr;

     if(argc != )        //第二个参数为客户端的Ip地址，必须要有
     {
         printf("usage: ./client <ipaddress>.\n");
         return ;
     }

     if((sockfd = socket(AF_INET, SOCK_STREAM, )) < )        //打开一个socket的文件描述符
     {
         printf("create socket error: %s(errno: %d).\n", strerror(errno), errno);
         return ;
     }

     memset(&servaddr, , sizeof(servaddr));
     servaddr.sin_family = AF_INET;
     servaddr.sin_port = htons();            //使用6666号端口
     if(inet_pton(AF_INET, argv[], &servaddr.sin_addr) <= )
     {
         printf("inet_pton error for %s.\n", argv[]);
         return ;
     }

     temperature = get_tem();        //获取温度值并返回给temperature
     gcvt(temperature, , temp);            //将温度值转换为字符串类型的
     memset(sendline, , sizeof(sendline));
     strcpy(sendline, "the degrees is ");
     strcat(sendline, temp);

     memset(timE, , sizeof(timE));
     time(&rawtime);
     timeinfo=localtime(&rawtime);
     strftime(timE,,"%y-%m-%d %I:%M:%S",timeinfo);            //获取当前时间

     strcat(sendline, "℃, time is ");
     strcat(sendline, timE);

     if(connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < )
     {
         ret = save_tem(sendline);                //若连接客户端失败则调用save_tem函数保存数据
         printf("connect error: %s(errno: %d)\n", strerror(errno), errno);
         return ;
     }

     if(send(sockfd, sendline, strlen(sendline), ) < )
     {
         printf("send msg error: %s(errno: %d)\n", strerror(errno), errno);
         return ;
     }
     else
     {
         read_sql(argv[]);                //如果可以连接数据库则读取数据库并发送
         delet_sql();                    //读取完了之后删除数据库
     }

     close(sockfd);                        //关闭socket文件描述符
     return ;
 } /* ----- End of main() ----- */

二、服务器代码

 #include<stdio.h>
 #include<stdlib.h>
 #include<string.h>
 #include<errno.h>
 #include<sys/types.h>
 #include<sys/socket.h>
 #include<netinet/in.h>
 #include <sys/time.h>
 #include<time.h>
 #include <sqlite3.h>

 #define MAXLINE 4096

 int save_tem(char *s_temp)
 {
     char sql[];
     sqlite3 *db;
     FILE *fd;

     sqlite3_open("tem.db", &db);
     memset(sql, '\0', );
     strcpy(sql, "create table tb(id INTEGER PRIMARY KEY, data TEXT)");
     sqlite3_exec(db, sql, NULL, NULL, NULL);

     memset(sql, '\0', );
     strcpy(sql, "insert into tb(data) values(\"");
     strcat(sql, s_temp);
     strcat(sql, "\")");
     sqlite3_exec(db, sql, NULL, NULL, NULL);
     sqlite3_close(db);
     return ;
 }

 int main(int argc, char** argv)
 {
     int         n;
     int         listenfd;
     int         connfd;
     char        buff[];
     struct  sockaddr_in     servaddr;

     if((listenfd = socket(AF_INET, SOCK_STREAM, )) == - )
     {
         printf("create socket error: %s(errno: %d)\n",strerror(errno),errno);
         exit();
     }

     memset(&servaddr, , sizeof(servaddr));
     servaddr.sin_family = AF_INET;
     servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
     servaddr.sin_port = htons();

     if(bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -)
     {
         printf("bind socket error: %s(errno: %d)\n",strerror(errno),errno);
         exit();
     }

     if(listen(listenfd, ) == -)
     {
         printf("listen socket error: %s(errno: %d)\n",strerror(errno),errno);
         exit();
     }

     printf("======waiting for client's request======\n");

     while()
     {
         memset(buff, , sizeof(buff));

         if((connfd = accept(listenfd, (struct sockaddr*)NULL, NULL)) == -)
         {
             printf("accept socket error: %s(errno: %d)",strerror(errno),errno);
             continue;
         }
         n = recv(connfd, buff, MAXLINE, );
         printf("%s\n", buff);
         save_tem(buff);
         close(connfd);
     }
     close(listenfd);
 }