【源文件main.c】
#include <stdio.h>
#include <stdlib.h> // system函數所在地
#include <string.h>
#include <conio.h>
#include "db.h"

int exit_flag = 0; // 程序退出標誌

void show_food()
{
    int type_id;
    char sql[100];
    char type_name[100];
    void *stmt1, *stmt2;

    int food_id;
    char food_name[100];
    float food_price;

    int i;
    char order_name[100];
    char place[100];
   
    stmt1 = db_query("SELECT * FROM Categories");
    db_bind_int(stmt1, 1, &type_id);
    db_bind_str(stmt1, 2, type_name, sizeof(type_name));

    system("cls"); // 清屏
    while (db_fetch(stmt1))
    {
        printf("------------------類別%d %s-------------------\n", type_id, type_name);

        sprintf_s(sql, sizeof(sql), "SELECT FoodID, FoodName, FoodPrice FROM Food WHERE FoodType = %d", type_id);
        stmt2 = db_query(sql);
        db_bind_int(stmt2, 1, &food_id);
        db_bind_str(stmt2, 2, food_name, sizeof(food_name));
        db_bind_float(stmt2, 3, &food_price);

        for (i = 0; db_fetch(stmt2); i++)
        {
            if (i % 3 == 0 && i != 0)
                putchar('\n');
            printf("%d.%s(%.1f元)\t", food_id, food_name, food_price);
        }
        putchar('\n');

        db_free(stmt2);
    }

    db_free(stmt1);

    printf("請輸入所選菜的編號: ");
    scanf_s("%d", &food_id);

    sprintf_s(sql, sizeof(sql), "SELECT * FROM Food WHERE FoodID = %d", food_id);
    if (!db_has_records(sql))
    {
        puts("該菜不存在！");
        _getch();
        system("cls");
        return;
    }

    fflush(stdin);
    printf("請輸入客戶名：");
    gets_s(order_name, sizeof(order_name));
    printf("請輸入用餐地點: ");
    gets_s(place, sizeof(place));
   
    stmt1 = db_prepare("INSERT INTO Orders (OrderName, FoodID, OrderPlace) VALUES (?, ?, ?)");
    db_set_str(stmt1, 1, order_name);
    db_set_int(stmt1, 2, &food_id);
    db_set_str(stmt1, 3, place);
    if (db_exec_stmt(stmt1, 1))
        puts("添加訂單成功");
    else
        puts("添加訂單失敗");
    _getch();
    system("cls");
}

void show_orders()
{
    void *s1;
    int order_id;
    char order_name[100];
    char food_name[100];
    char order_place[100];
    char order_time[100];

    system("cls");
    puts("------------------訂單------------------");

    s1 = db_query("SELECT OrderID, OrderName, (SELECT FoodName FROM Food WHERE FoodID = Orders.FoodID), OrderPlace, OrderTime FROM Orders ORDER BY OrderID DESC");
    db_bind_int(s1, 1, &order_id);
    db_bind_str(s1, 2, order_name, sizeof(order_name));
    db_bind_str(s1, 3, food_name, sizeof(food_name));
    db_bind_str(s1, 4, order_place, sizeof(order_place));
    db_bind_str(s1, 5, order_time, sizeof(order_time));
    puts("單號\t客戶\t菜名\t地點\t時間");
    while (db_fetch(s1))
    {
        printf("%4d %8s %8s %8s %s\n", order_id, order_name, food_name, order_place, order_time);
    }
    db_free(s1);

    _getch();
    system("cls");
}

void handle_order()
{
    int order_id, food_id;
    char sql[100];
    char customer_id[100];
    char comment[500];
    void *stmt;

    printf("請輸入訂單號: ");
    scanf_s("%d", &order_id);

    sprintf_s(sql, sizeof(sql), "SELECT FoodID FROM Orders WHERE OrderID = %d", order_id);
    stmt = db_query(sql);
    db_bind_int(stmt, 1, &food_id);
    if (!db_fetch(stmt))
    {
        db_free(stmt);
        puts("該訂單不存在!");
        _getch();
        system("cls");
        return;
    }
    db_free(stmt);

    printf("請輸入客戶身份證號碼: ");
    fflush(stdin);
    gets_s(customer_id, sizeof(customer_id));

    printf("請輸入客戶評價內容: ");
    gets_s(comment, sizeof(comment));

    stmt = db_prepare("INSERT INTO Comments (FoodID, CustomerID, Comment) VALUES (?, ?, ?)");
    db_set_int(stmt, 1, &food_id);
    db_set_str(stmt, 2, customer_id);
    db_set_str(stmt, 3, comment);
    if (db_exec_stmt(stmt, 1))
    {
        sprintf_s(sql, sizeof(sql), "DELETE FROM Orders WHERE OrderID = %d", order_id);
        db_exec(sql);
        puts("處理訂單成功");
    }
    else
        puts("處理訂單失敗");
   
    _getch();
    system("cls");
}

void show_comments()
{
    int comment_id, food_id;
    char food_name[100];
    char customer_id[100];
    char comment[500];
    char time[30];
    void *stmt, *stmt2;

    system("cls");
    stmt = db_query("SELECT * FROM Comments ORDER BY CommentID DESC");
    db_bind_int(stmt, 1, &comment_id);
    db_bind_int(stmt, 2, &food_id);
    db_bind_str(stmt, 3, customer_id, sizeof(customer_id));
    db_bind_str(stmt, 4, comment, sizeof(comment));
    db_bind_str(stmt, 5, time, sizeof(time));
    while (db_fetch(stmt))
    {
        stmt2 = db_prepare("SELECT FoodName FROM Food WHERE FoodID = ?");
        db_set_int(stmt2, 1, &food_id);
        db_exec_stmt(stmt2, 0);
        db_bind_str(stmt2, 1, food_name, sizeof(food_name));
        db_fetch(stmt2);
        printf("--------------------評價%d: %d.%s-----------------\n", comment_id, food_id, food_name);
        printf(" 客戶身份證號: %s\n", customer_id);
        printf(" 評價內容: %s\n", comment);
        printf(" 評價時間: %s\n", time);
        puts("------------------------------------------------");
        db_free(stmt2);
    }
    db_free(stmt);

    _getch();
    system("cls");
}

void show_menu()
{
    int n;
    puts("------------------歡迎使用點餐系統------------------");
    puts("--- 1.訂餐                                    -----");
    puts("--- 2.查看訂單                                -----");
    puts("--- 3.處理訂單                                -----");
    puts("--- 4.查看評價                                -----");
    puts("--- 5.退出                                    -----");
    puts("---------------------------------------------------");
    printf("請輸入: ");
    scanf_s("%d", &n);
   
    switch (n)
    {
    case 1:
        show_food();
        break;
    case 2:
        show_orders();
        break;
    case 3:
        handle_order();
        break;
    case 4:
        show_comments();
        break;
    case 5:
        exit_flag = 1;
        puts("謝謝您的使用....");
        break;
    default:
        puts("輸入錯誤, 請重新輸入!");
    }
}

void main()
{
    if (db_connect("data.mdb"))
    {
        while (!exit_flag)
        {
            show_menu();
        }
    }
    db_disconnect();
}

【頭文件db.h】
/* 數據庫連接與斷開 */
int db_connect(char *dbname);
void db_disconnect();

/* Prepared Statement 相關 */
void *db_prepare(char *sql);
int db_exec_stmt(void *stmt, int free);
// 設置SQL語句中的問號
void db_set_int(void *stmt, int i, int *p);
void db_set_str(void *stmt, int i, char *s);


/* 直接執行查詢，不Prepare */
void *db_query(char *sql); // 執行SELECT查詢，需要手動釋放資源
void db_exec(char *sql); // 執行普通查詢
int db_has_records(char *sql); // 直接執行SELECT查詢，判斷結果集是否有記錄
void db_free(void *stmt); // 釋放db_query的資源

/* 記錄集操作 */
int db_fetch(void *stmt); // 獲取一行記錄
// 綁定字段到變量上
void db_bind_int(void *stmt, int col, int *p); // 以整數類型保存第col列的內容
void db_bind_str(void *stmt, int col, char *buf, int len); // 以字符串類型保存第col列的內容
void db_bind_float(void *stmt, int col, float *p); // 以小數類型保存第col列的內容

【源文件db.c】
/*
這個文件里封裝了很多操作數據庫的函數
參考資料：https://msdn.microsoft.com/en-us/library/ms714562%28v=vs.85%29.aspx
*/

#include <stdio.h>
#include <conio.h>
#include <Windows.h>
#include <sqlext.h>
#include "db.h"

#define DB_DSN "Driver={Microsoft Access Driver (*.mdb)};DBQ=%s;"

SQLHENV hEnv;
SQLHDBC hConn;
SQLRETURN rc;

int db_connect(char *dbname)
{
    char szDSN[100]; // 數據庫連接字符串
    char szCode[6] = ""; // 錯誤代碼
    char szMsg[256] = ""; // 錯誤信息

    SQLAllocHandle(SQL_HANDLE_ENV, NULL, &hEnv);
    SQLSetEnvAttr(hEnv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3_80, (SQLINTEGER)NULL);
    SQLAllocHandle(SQL_HANDLE_DBC, hEnv, &hConn);
   
    sprintf_s(szDSN, sizeof(szDSN), DB_DSN, dbname); // 根據數據庫文件名生成數據庫連接字符串
    rc = SQLDriverConnectA(hConn, NULL, (SQLCHAR *)szDSN, SQL_NTS, NULL, (SQLSMALLINT)NULL, NULL, (SQLSMALLINT)NULL); // 根據連接字符串連接數據庫
    if (!SQL_SUCCEEDED(rc))
    {
        // 連接失敗的錯誤提示
        puts("無法連接數據庫！");
        rc = SQLGetDiagRecA(SQL_HANDLE_DBC, hConn, 1, (SQLCHAR *)szCode, NULL, (SQLCHAR *)szMsg, sizeof(szMsg) - 1, NULL);
        if (SUCCEEDED(rc))
        {
            printf("錯誤代碼: %s\n", szCode);
            printf("錯誤信息: %s\n", szMsg);
        }
        else
            puts("未知錯誤");

        _getch();

        return 0; // 連接失敗時，函數返回0
    }
    return 1; // 連接成功時，函數返回1
}

void db_disconnect()
{
    SQLDisconnect(hConn);
    SQLFreeHandle(SQL_HANDLE_DBC, hConn);
    SQLFreeHandle(SQL_HANDLE_ENV, hEnv);
}




void *db_prepare(char *sql)
{
    SQLHSTMT hStmt;
    SQLAllocHandle(SQL_HANDLE_STMT, hConn, &hStmt);
    SQLPrepareA(hStmt, (SQLCHAR *)sql, strlen(sql));
    return hStmt;
}

int db_exec_stmt(void *stmt, int free)
{
    int f = SQL_SUCCEEDED(SQLExecute(stmt));
    if (free)
        db_free(stmt);
    return f;
}

void db_set_int(void *stmt, int i, int *p)
{
    static SQLLEN size = sizeof(int); // 該變量的地址必須固定, 所以要加static
    SQLBindParameter(stmt, i, SQL_PARAM_INPUT, SQL_C_LONG, SQL_INTEGER, (SQLUINTEGER)NULL, (SQLSMALLINT)NULL, p, (SQLINTEGER)NULL, &size); // 整型變量的地址也必須固定
}


void db_set_str(void *stmt, int i, char *s)
{
    static SQLLEN len = SQL_NTS;
    SQLBindParameter(stmt, i, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_VARCHAR, strlen(s), (SQLSMALLINT)NULL, s, (SQLINTEGER)NULL, &len);
}


void *db_query(char *sql)
{
    void *stmt = db_prepare(sql);
    SQLExecute(stmt);
    return stmt;
}

void db_exec(char *sql)
{
    void *stmt = db_query(sql);
    db_free(stmt);
}

int db_has_records(char *sql)
{
    void *stmt = db_query(sql);
    int r = db_fetch(stmt);
    db_free(stmt);
    return r;
}

void db_free(void *stmt)
{
    SQLFreeHandle(SQL_HANDLE_STMT, stmt);
}

int db_fetch(void *stmt)
{
    return SQL_SUCCEEDED(SQLFetch(stmt));
}


void db_bind_int(void *stmt, int col, int *p)
{
    SQLBindCol(stmt, col, SQL_C_LONG, p, sizeof(int), NULL);
}


void db_bind_str(void *stmt, int col, char *buf, int len)
{
    SQLBindCol(stmt, col, SQL_C_CHAR, buf, len, NULL);
}

void db_bind_float(void *stmt, int col, float *p)
{
    SQLBindCol(stmt, col, SQL_C_FLOAT, p, sizeof(float), NULL);
}

【數據庫】

32位ODBC Access 2010驅動（accdb）下載地址：
https://www.microsoft.com/en-us/download/confirmation.aspx?id=13255