超市食品信息管理系统运用SQL 作为后台数据库，运用c++作为前台数据的c++代码

以下是一个简单的超市食品信息管理系统的 C++ 代码，使用 SQL 作为后台数据库：

#include <iostream>
#include <windows.h>
#include <sqlext.h>
#include <sqltypes.h>
#include <sql.h>

using namespace std;

void showMenu();
void addProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle);
void searchProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle);
void updateProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle);
void deleteProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle);
void showAllProducts(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle);

int main()
{
    // Initialize variables
    SQLHANDLE sqlEnvHandle;
    SQLHANDLE sqlConnHandle;
    SQLHANDLE sqlStmtHandle;
    SQLRETURN retcode;

    // Allocate an environment handle
    retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &sqlEnvHandle);
    // Set the ODBC version environment attribute
    retcode = SQLSetEnvAttr(sqlEnvHandle, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0);
    // Allocate a connection handle
    retcode = SQLAllocHandle(SQL_HANDLE_DBC, sqlEnvHandle, &sqlConnHandle);
    // Connect to the database using DSN
    retcode = SQLConnect(sqlConnHandle, (SQLCHAR*)"DSN", SQL_NTS, NULL, 0, NULL, 0);

    if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
    {
        cout << "Connected to database." << endl;

        // Allocate a statement handle
        retcode = SQLAllocHandle(SQL_HANDLE_STMT, sqlConnHandle, &sqlStmtHandle);

        // Show the main menu
        showMenu();

        // Free the statement handle
        SQLFreeHandle(SQL_HANDLE_STMT, sqlStmtHandle);
        // Disconnect from the database
        SQLDisconnect(sqlConnHandle);
    }
    else
    {
        cout << "Failed to connect to database." << endl;
    }

    // Free the connection handle
    SQLFreeHandle(SQL_HANDLE_DBC, sqlConnHandle);
    // Free the environment handle
    SQLFreeHandle(SQL_HANDLE_ENV, sqlEnvHandle);

    return 0;
}

void showMenu()
{
    SQLHANDLE sqlConnHandle;
    SQLHANDLE sqlStmtHandle;
    SQLRETURN retcode;

    // Allocate an environment handle
    retcode = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, &sqlConnHandle);
    // Set the ODBC version environment attribute
    retcode = SQLSetEnvAttr(sqlConnHandle, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0);
    // Allocate a connection handle
    retcode = SQLAllocHandle(SQL_HANDLE_DBC, sqlConnHandle, &sqlConnHandle);
    // Connect to the database using DSN
    retcode = SQLConnect(sqlConnHandle, (SQLCHAR*)"DSN", SQL_NTS, NULL, 0, NULL, 0);

    int choice;

    do
    {
        cout << endl;
        cout << "1. Add a product" << endl;
        cout << "2. Search for a product" << endl;
        cout << "3. Update a product" << endl;
        cout << "4. Delete a product" << endl;
        cout << "5. Show all products" << endl;
        cout << "6. Exit" << endl;
        cout << endl;
        cout << "Enter your choice: ";
        cin >> choice;

        switch (choice)
        {
        case 1:
            addProduct(sqlConnHandle, sqlStmtHandle);
            break;
        case 2:
            searchProduct(sqlConnHandle, sqlStmtHandle);
            break;
        case 3:
            updateProduct(sqlConnHandle, sqlStmtHandle);
            break;
        case 4:
            deleteProduct(sqlConnHandle, sqlStmtHandle);
            break;
        case 5:
            showAllProducts(sqlConnHandle, sqlStmtHandle);
            break;
        case 6:
            cout << "Exiting..." << endl;
            break;
        default:
            cout << "Invalid choice. Please try again." << endl;
            break;
        }
    } while (choice != 6);

    // Disconnect from the database
    SQLDisconnect(sqlConnHandle);
    // Free the connection handle
    SQLFreeHandle(SQL_HANDLE_DBC, sqlConnHandle);
    // Free the environment handle
    SQLFreeHandle(SQL_HANDLE_ENV, sqlConnHandle);
}

void addProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle)
{
    SQLRETURN retcode;
    char name[50];
    float price;
    int quantity;

    cout << endl;
    cout << "Enter product name: ";
    cin.ignore();
    cin.getline(name, 50);
    cout << "Enter product price: ";
    cin >> price;
    cout << "Enter product quantity: ";
    cin >> quantity;

    // Prepare the SQL statement
    retcode = SQLPrepare(sqlStmtHandle, (SQLCHAR*)"INSERT INTO products (name, price, quantity) VALUES (?, ?, ?)", SQL_NTS);
    // Bind parameters
    SQLBindParameter(sqlStmtHandle, 1, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_VARCHAR, 50, 0, name, 0, NULL);
    SQLBindParameter(sqlStmtHandle, 2, SQL_PARAM_INPUT, SQL_C_FLOAT, SQL_REAL, 0, 0, &price, 0, NULL);
    SQLBindParameter(sqlStmtHandle, 3, SQL_PARAM_INPUT, SQL_C_LONG, SQL_INTEGER, 0, 0, &quantity, 0, NULL);
    // Execute the SQL statement
    retcode = SQLExecute(sqlStmtHandle);

    if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
    {
        cout << "Product added successfully." << endl;
    }
    else
    {
        cout << "Failed to add product." << endl;
    }
}

void searchProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle)
{
    SQLRETURN retcode;
    char name[50];

    cout << endl;
    cout << "Enter product name: ";
    cin.ignore();
    cin.getline(name, 50);

    // Prepare the SQL statement
    retcode = SQLPrepare(sqlStmtHandle, (SQLCHAR*)"SELECT * FROM products WHERE name = ?", SQL_NTS);
    // Bind parameter
    SQLBindParameter(sqlStmtHandle, 1, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_VARCHAR, 50, 0, name, 0, NULL);
    // Execute the SQL statement
    retcode = SQLExecute(sqlStmtHandle);

    if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
    {
        // Fetch the data
        SQLCHAR name[50];
        float price;
        int quantity;

        SQLBindCol(sqlStmtHandle, 1, SQL_C_CHAR, name, 50, NULL);
        SQLBindCol(sqlStmtHandle, 2, SQL_C_FLOAT, &price, 0, NULL);
        SQLBindCol(sqlStmtHandle, 3, SQL_C_LONG, &quantity, 0, NULL);

        while (SQLFetch(sqlStmtHandle) == SQL_SUCCESS)
        {
            cout << "Product name: " << name << endl;
            cout << "Product price: " << price << endl;
            cout << "Product quantity: " << quantity << endl;
            cout << endl;
        }
    }
    else
    {
        cout << "Failed to search for product." << endl;
    }
}

void updateProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle)
{
    SQLRETURN retcode;
    char name[50];
    float price;
    int quantity;

    cout << endl;
    cout << "Enter product name: ";
    cin.ignore();
    cin.getline(name, 50);
    cout << "Enter new product price: ";
    cin >> price;
    cout << "Enter new product quantity: ";
    cin >> quantity;

    // Prepare the SQL statement
    retcode = SQLPrepare(sqlStmtHandle, (SQLCHAR*)"UPDATE products SET price = ?, quantity = ? WHERE name = ?", SQL_NTS);
    // Bind parameters
    SQLBindParameter(sqlStmtHandle, 1, SQL_PARAM_INPUT, SQL_C_FLOAT, SQL_REAL, 0, 0, &price, 0, NULL);
    SQLBindParameter(sqlStmtHandle, 2, SQL_PARAM_INPUT, SQL_C_LONG, SQL_INTEGER, 0, 0, &quantity, 0, NULL);
    SQLBindParameter(sqlStmtHandle, 3, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_VARCHAR, 50, 0, name, 0, NULL);
    // Execute the SQL statement
    retcode = SQLExecute(sqlStmtHandle);

    if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
    {
        cout << "Product updated successfully." << endl;
    }
    else
    {
        cout << "Failed to update product." << endl;
    }
}

void deleteProduct(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle)
{
    SQLRETURN retcode;
    char name[50];

    cout << endl;
    cout << "Enter product name: ";
    cin.ignore();
    cin.getline(name, 50);

    // Prepare the SQL statement
    retcode = SQLPrepare(sqlStmtHandle, (SQLCHAR*)"DELETE FROM products WHERE name = ?", SQL_NTS);
    // Bind parameter
    SQLBindParameter(sqlStmtHandle, 1, SQL_PARAM_INPUT, SQL_C_CHAR, SQL_VARCHAR, 50, 0, name, 0, NULL);
    // Execute the SQL statement
    retcode = SQLExecute(sqlStmtHandle);

    if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
    {
        cout << "Product deleted successfully." << endl;
    }
    else
    {
        cout << "Failed to delete product." << endl;
    }
}

void showAllProducts(SQLHANDLE& sqlConnHandle, SQLHANDLE& sqlStmtHandle)
{
    SQLRETURN retcode;

    // Prepare the SQL statement
    retcode = SQLPrepare(sqlStmtHandle, (SQLCHAR*)"SELECT * FROM products", SQL_NTS);
    // Execute the SQL statement
    retcode = SQLExecute(sqlStmtHandle);

    if (retcode == SQL_SUCCESS || retcode == SQL_SUCCESS_WITH_INFO)
    {
        // Fetch the data
        SQLCHAR name[50];
        float price;
        int quantity;

        SQLBindCol(sqlStmtHandle, 1, SQL_C_CHAR, name, 50, NULL);
        SQLBindCol(sqlStmtHandle, 2, SQL_C_FLOAT, &price, 0, NULL);
        SQLBindCol(sqlStmtHandle, 3, SQL_C_LONG, &quantity, 0, NULL);

        while (SQLFetch(sqlStmtHandle) == SQL_SUCCESS)
        {
            cout << "Product name: " << name << endl;
            cout << "Product price: " << price << endl;
            cout << "Product quantity: " << quantity << endl;
            cout << endl;
        }
    }
    else
    {
        cout << "Failed to show all products." << endl;
    }
}

请注意，在使用此代码之前，需要先创建一个名为“DSN”的 ODBC 数据源，并在其中创建一个名为“products”的数据表，该数据表应包含三个列：name、price 和 quantity。