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[4096]; 
/********************************************************************************
 *  Description:
 *   Input Args:
 *  Output Args:
 * Return Value:
 ********************************************************************************/
double get_tem(void)        //获取温度的函数
{
    int fd;
    double result = 0;
    unsigned char buff[2];
    unsigned short temp = 0;
    int flag = 0;

    if ((fd=open("/dev/ds18b20",O_RDWR | O_NDELAY | O_NOCTTY)) < 0)
    {
        perror("open device ds18b20 failed.
");
        exit(1);
    }

    printf("open device ds18b20 success.
");
    
    read(fd, buff, sizeof(buff));
    temp=((unsigned short)buff[1])<<8;
    temp|=(unsigned short)buff[0];
    result=0.0625*((double)temp);
    close(fd);
    printf("temperature is %4f 
", result);
    return result;
}

int save_tem(char *s_temp)            //将数据保存到数据库
{
    char sql[128];
    sqlite3 *db;
    FILE *fd;

    sqlite3_open("temperature.db", &db);
    memset(sql, '', 128);
    strcpy(sql, "create table tb(id INTEGER PRIMARY KEY, data TEXT)");
    sqlite3_exec(db, sql, NULL, NULL, NULL);

    memset(sql, '', 128);
    strcpy(sql, "insert into tb(data) values("");
    strcat(sql, s_temp);
    strcat(sql, "")");
    sqlite3_exec(db, sql, NULL, NULL, NULL);
    sqlite3_close(db);
    return 0;
}

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, 0)) < 0)
    {
        printf("create socket error: %s(errno: %d).
", strerror(errno), errno);
        return 0;
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(6666);
    if(inet_pton(AF_INET, addr, &servaddr.sin_addr) <= 0)
    {
        printf("inet_pton error for %s.
", addr);
        return 0;
    }

    memset(sendline, 0, sizeof(sendline));
    if(connect(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) < 0)
    {
        printf("connect error: %s(errno: %d)
", strerror(errno), errno);
        return 0;
    }

    if(send(sockfd, values[1], strlen(values[1]), 0) < 0)
    {
        printf("send msg error: %s(errno: %d)
", strerror(errno), errno);
        return 0;
    }
    close(sockfd);
    return 0;
}

int read_sql(char *addr)        //读取数据库中的数据并发送的函数
{
    char sql[128];
    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 0;
}

int delet_sql(void)                //删除数据库中表的函数
{
    char sql[128];
    sqlite3 *db;

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

    sqlite3_close(db);
    return 0;
}

int main (int argc, char **argv)
{
    double      temperature;
    int         sockfd;
    int         ret;
    char        timE[80];
    time_t      rawtime;
    char        temp[25];
    char        sendline[MAXLINE];
    char        recvline[MAXLINE];
    struct tm* timeinfo;
    struct sockaddr_in servaddr;

    if(argc != 2)        //第二个参数为客户端的Ip地址，必须要有
    {
        printf("usage: ./client <ipaddress>.
");
        return 0;
    }

    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)        //打开一个socket的文件描述符
    {
        printf("create socket error: %s(errno: %d).
", strerror(errno), errno);
        return 0;
    }
    
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(6666);            //使用6666号端口
    if(inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0)
    {
        printf("inet_pton error for %s.
", argv[1]);
        return 0;
    }

    temperature = get_tem();        //获取温度值并返回给temperature
    gcvt(temperature, 4, temp);            //将温度值转换为字符串类型的
    memset(sendline, 0, sizeof(sendline));
    strcpy(sendline, "the degrees is ");
    strcat(sendline, temp);
   
    memset(timE, 0, sizeof(timE));
    time(&rawtime);
    timeinfo=localtime(&rawtime);
    strftime(timE,80,"%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)) < 0)
    {
        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)
", strerror(errno), errno);
        return 0;
    }
    
    if(send(sockfd, sendline, strlen(sendline), 0) < 0)
    {
        printf("send msg error: %s(errno: %d)
", strerror(errno), errno);
        return 0;
    }
    else
    {
        read_sql(argv[1]);                //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 0;
} /* ----- 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[128];
    sqlite3 *db;
    FILE *fd;

    sqlite3_open("tem.db", &db);
    memset(sql, '', 128);
    strcpy(sql, "create table tb(id INTEGER PRIMARY KEY, data TEXT)");
    sqlite3_exec(db, sql, NULL, NULL, NULL);

    memset(sql, '', 128);
    strcpy(sql, "insert into tb(data) values("");
    strcat(sql, s_temp);
    strcat(sql, "")");
    sqlite3_exec(db, sql, NULL, NULL, NULL);
    sqlite3_close(db);
    return 0;
}

int main(int argc, char** argv)
{
    int         n;
    int         listenfd;
    int         connfd;
    char        buff[4096];
    struct  sockaddr_in     servaddr;
    
    if((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 )
    {
        printf("create socket error: %s(errno: %d)
",strerror(errno),errno);
        exit(0);
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(6666);

    if(bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) == -1)
    {
        printf("bind socket error: %s(errno: %d)
",strerror(errno),errno);
        exit(0);
    }

    if(listen(listenfd, 10) == -1)
    {
        printf("listen socket error: %s(errno: %d)
",strerror(errno),errno);
        exit(0);
    }

    printf("======waiting for client's request======
");
    
    while(1)
    {
        memset(buff, 0, sizeof(buff));
        
        if((connfd = accept(listenfd, (struct sockaddr*)NULL, NULL)) == -1)
        {
            printf("accept socket error: %s(errno: %d)",strerror(errno),errno);
            continue;
        }
        n = recv(connfd, buff, MAXLINE, 0);
        printf("%s
", buff);
        save_tem(buff);
        close(connfd);
    }
    close(listenfd);
}