python选课系统作业

### Python 开发学生选课系统示例

#### 创建项目环境
为了构建一个稳定可靠的学生选课系统，建议使用虚拟环境来隔离依赖项。通过命令行工具安装并激活虚拟环境：

python -m venv myenv
source myenv/bin/activate  # Linux 或 macOS
myenv\Scripts\activate     # Windows

接着，在环境中安装必要的包，如 `PyQt6` 和 `mysql-connector-python`。

pip install PyQt6 mysql-connector-python

#### 数据库连接模块
定义用于处理 MySQL 数据库操作的基础类，以便于后续的功能扩展和维护[^1]。

import mysql.connector


class DatabaseConnection:
    def __init__(self, host="localhost", user="root", password="", database=""):
        self.connection = None
        try:
            self.connection = mysql.connector.connect(
                host=host,
                user=user,
                passwd=password,
                db=database
            )
            if self.connection.is_connected():
                print("Successfully connected to the database.")
        except Exception as e:
            print(f"Error connecting to MySQL platform: {e}")

    def execute_query(self, query, params=None):
        cursor = self.connection.cursor()
        result = None
        try:
            cursor.execute(query, params)
            result = cursor.fetchall()
            self.connection.commit()
        except Exception as error:
            print(f"The error '{error}' occurred")
        finally:
            if cursor is not None and self.connection is not None:
                cursor.close()

        return result
    
    def close_connection(self):
        if self.connection is not None:
            self.connection.close()

#### 主窗口设计
利用 Qt Designer 设计图形化界面，并将其转换成 Python 文件。这里展示如何加载 `.ui` 文件以及初始化主窗口中的组件[^2]。

from PyQt6 import uic
from PyQt6.QtWidgets import QApplication, QMainWindow


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        uic.loadUi('main_window.ui', self)

if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()

#### 功能逻辑实现
针对具体业务需求编写相应的函数，比如添加新课程、删除已有课程、显示所有可选项等。下面给出部分核心方法的伪代码表示形式[^3]。

def add_course(course_name, teacher_name, max_students):
    """向数据库中插入一条新的课程记录"""
    pass

def remove_course_by_id(course_id):
    """根据ID移除指定的一门课程"""
    pass

def list_all_courses():
    """获取当前学期开设的所有课程列表"""
    pass

def enroll_student(student_id, selected_courses_ids):
    """允许某位同学注册选定的若干门科目"""
    
    # 验证是否有重复报名情况发生
    existing_selections = get_current_enrollment_status(student_id)
    conflicting_timeslots = check_time_conflicts(selected_courses_ids + existing_selections)
    
    if conflicting_timeslots:
        raise ValueError("Selected courses contain time conflicts!")
        
    total_credits = sum([get_credit_hours(cid) for cid in selected_courses_ids])
    if total_credits > MAX_CREDITS_PER_SEMESTER:
        raise ValueError("Total credits exceed limit!")

    update_database_with_new_selections(student_id, selected_courses_ids)


def drop_selected_courses(student_id, deselected_courses_ids):
    """取消已登记的选择"""
    pass