阅读引言: 本文将会从环境sqlite3的安装、数据库的基础知识、sqlite3命令、以及sqlite的sql语句最后还有一个完整的代码实例, 相信仔细学习完这篇内容之后大家一定能有所收获。
目录
一、数据库的基础知识
1.数据库的基本概念
2.常用数据库
3.嵌入式数据库
4.sqlite3基础
5.创建数据库
6.数据库的相关术语
二.Sqlite3安装
sudo apt-get install
dpkg -s sqlite3
按道理来讲, 到这一步就结束了, 但是在实际的代码编译中, 找不到sqlite3.h头文件, 也链接不到对应的sql接口的实现。大家安装完可以先去/usr/include目录下看有没有对应的头文件, 没有的话这样干。安装sqlite3的库包。
sudo apt-get install libsqlite3-dev
三、Sqlite3命令
简单演示
四、Sqlite3语句
简单演示
五、Sqlite编程接口
六、代码实例
实例软件结构如下:
Makefile
OBJ=$(wildcard ./*.c)
all:$(OBJ)
gcc *.c -o test -lsqlite3
main.c
#include "sqlite_method.h"
/* hint user input */
void hint_display();
/* main */
int main(int argc, const char *argv[])
{
sqlite3 *db;
char *errmsg;
char input;
if(sqlite3_open(DATABASE_PATH, &db) != SQLITE_OK) {
printf("%s\n", sqlite3_errmsg(db));
return -1;
} else {
printf("open database [%s] success\n", DATABASE_PATH);
}
if(sqlite3_exec(db, "create table if not exists exercise(id integer, name text, score integer);", \
NULL, NULL, &errmsg) != SQLITE_OK) {
printf("sqlite3_exec failed, line: %d\n", __LINE__);
}
/* handle user input */
while(1) {
hint_display();
scanf("%c", &input);
switch(input) {
case 'i':
insert_handle(db);
getchar();
break;
case 'd':
delete_handle(db);
getchar();
break;
case 'q':
query_handle(db);
getchar();
break;
case 'u':
update_handle(db);
getchar();
break;
case '!':
quit_handle(db);
getchar();
break;
default:
printf("invalid option!\n");
}
}
return 0;
}
void hint_display()
{
printf("**********************************************************\n");
printf("*i: insert d: delete q: query u: update !:exit*\n");
printf("**********************************************************\n");
}
sqlite_method.h
#ifndef _SQLITE_METHOD_H_
#define _SQLITE_METHOD_H_
/*Author: Hewei
*Date: 2024-3-30
*Brife: database operator
* */
#include <sqlite3.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#define DATABASE_PATH "./exercise.db"
#define N 256
void insert_handle(sqlite3 *db);
void delete_handle(sqlite3 *db);
void query_handle(sqlite3 *db);
void update_handle(sqlite3 *db);
void quit_handle(sqlite3 *db);
#endif
sqlite_method.c
#include "sqlite_method.h"
void insert_handle(sqlite3 *db)
{
int id;
char name[128] ={0};
int score;
char buff[N] = {0};
char *errmsg;
printf("Please input id:");
scanf("%d", &id);
printf("Please input name:");
scanf("%s", name);
//getchar(); method 1
printf("Please input score:");
//scanf("% c%d", &score); method 2
scanf("%*c%d", &score);
sprintf(buff, "insert into exercise values(%d, '%s', %d)", id, name, score);
if(sqlite3_exec(db, buff, NULL, NULL, &errmsg) != SQLITE_OK) {
printf("%s\n", errmsg);
} else {
printf("\n\n\n");
printf("insert operator success!|\n");
}
}
void delete_handle(sqlite3 *db)
{
int id;
char buff[N] = {0};
char *errmsg;
printf("Please input delete id:");
scanf("%d", &id);
snprintf(buff, sizeof(buff), "delete from exercise where id = %d", id);
if(sqlite3_exec(db, buff, NULL, NULL, &errmsg) != SQLITE_OK) {
printf("%s\n", errmsg);
} else {
printf("\n\n\n");
printf("delete operator success!|\n");
}
}
int query_callback(void *arg, int f_num, char **value, char **name)
{
int i;
static int count = 0;
if(count == 0) {
for(i = 0; i < f_num; i++) {
printf("%-10s", name[i]);
}
count = 1;
putchar(10);
}
for(i = 0; i < f_num; i++) {
printf("%-10s", value[i]);
}
puts("");
return 0;
}
void query_handle(sqlite3 *db)
{
char buff[N] = {0};
char *errmsg;
sprintf(buff, "select * from exercise");
if(sqlite3_exec(db, buff, query_callback, NULL, &errmsg) != SQLITE_OK) {
printf("%s\n", errmsg);
} else {
printf("\n\n\n");
printf("query operator success!|\n");
}
}
void update_handle(sqlite3 *db)
{
char buff[128];
char *errmsg;
int id, score;
printf("Please input you want update id:");
scanf("%d", &id);
printf("Please input you want update score:");
scanf("%d", &score);
sprintf(buff, "update exercise set score = %d where id = %d\n", score, id);
if(sqlite3_exec(db, buff, NULL, NULL, &errmsg) != SQLITE_OK) {
printf("%s\n", errmsg);
} else {
printf("\n\n\n");
printf("update operator success!\n");
}
}
void quit_handle(sqlite3 *db)
{
printf("\n\n\n");
printf("database os exit success!\n");
sqlite3_close(db);
exit(1);
}
七、简单总结
1. 关系型数据库其实就是execl那种类似的表格, 不是什么高深的东西
2. Sqlite3的特点: 体积小、简单、高效、本地存储、源码开放。
好了, 老规矩希望对有需要的人有帮助。因为这个我实现得不是很规范,看不懂的地方随时欢迎私信。