用php写一个停车场管理系统根据停放时间计价

好的，我可以为您提供一个简单的停车场管理系统，用PHP编写，实现根据停放时间计价的功能。

首先，我们需要一个数据库来存储停车场的信息。我们可以创建一个名为“parking”的数据库，其中包含两个表：一个名为“parking_lot”的表，用于存储停车场的信息，另一个名为“parking_record”的表，用于存储停车记录。

CREATE DATABASE parking;

USE parking;

CREATE TABLE parking_lot (
    id INT(11) PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(50) NOT NULL,
    capacity INT(11) NOT NULL
);

CREATE TABLE parking_record (
    id INT(11) PRIMARY KEY AUTO_INCREMENT,
    license_plate VARCHAR(20) NOT NULL,
    enter_time DATETIME NOT NULL,
    exit_time DATETIME,
    parking_lot_id INT(11) NOT NULL,
    price DECIMAL(10,2)
);

接下来，我们需要创建一个PHP文件，用于处理停车场的逻辑。首先，我们需要连接到数据库。

<?php

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "parking";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

然后，我们可以创建一个函数来添加停车场信息。

function addParkingLot($name, $capacity) {
    global $conn;

    $sql = "INSERT INTO parking_lot (name, capacity) VALUES ('$name', $capacity)";

    if ($conn->query($sql) === TRUE) {
        echo "Parking lot added successfully.";
    } else {
        echo "Error adding parking lot: " . $conn->error;
    }
}

接下来，我们需要创建一个函数来记录车辆进入停车场。

function enterParkingLot($license_plate, $parking_lot_id) {
    global $conn;

    $sql = "INSERT INTO parking_record (license_plate, enter_time, parking_lot_id) VALUES ('$license_plate', NOW(), $parking_lot_id)";

    if ($conn->query($sql) === TRUE) {
        echo "Vehicle entered parking lot successfully.";
    } else {
        echo "Error entering parking lot: " . $conn->error;
    }
}

然后，我们需要创建一个函数来记录车辆离开停车场，并计算停车费用。

function exitParkingLot($license_plate) {
    global $conn;

    $sql = "SELECT * FROM parking_record WHERE license_plate = '$license_plate' AND exit_time IS NULL";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        $row = $result->fetch_assoc();
        $enter_time = strtotime($row["enter_time"]);
        $exit_time = time();
        $parking_duration = ($exit_time - $enter_time) / 60; // in minutes

        // calculate price based on parking duration
        $price = 0.0;
        if ($parking_duration <= 60) {
            $price = 5.0;
        } else if ($parking_duration <= 120) {
            $price = 8.0;
        } else if ($parking_duration <= 180) {
            $price = 11.0;
        } else {
            $price = 11.0 + ceil(($parking_duration - 180) / 60) * 3.0;
        }

        // update parking record with exit time and price
        $sql = "UPDATE parking_record SET exit_time = NOW(), price = $price WHERE id = " . $row["id"];

        if ($conn->query($sql) === TRUE) {
            echo "Vehicle exited parking lot successfully. Price: $price";
        } else {
            echo "Error exiting parking lot: " . $conn->error;
        }
    } else {
        echo "Vehicle not found in parking lot or already exited.";
    }
}

最后，我们可以测试一下这些函数是否正常工作。

addParkingLot("Lot A", 50);

enterParkingLot("ABC123", 1);

exitParkingLot("ABC123");

当我们运行这个PHP文件时，它应该会输出以下结果：

Parking lot added successfully.
Vehicle entered parking lot successfully.
Vehicle exited parking lot successfully. Price: 5

这就是一个简单的用PHP编写的停车场管理系统，它可以根据停放时间计算停车费用。当然，这只是一个简单的示例，实际使用时还需要考虑更多的功能和安全性。