Django 小實例S1 簡易學生選課管理系統 9 創建課程模型(model)

Django 小實例S1 簡易學生選課管理系統 第9節——創建課程模型(model)
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作者自我介紹：b站小UP主，時常直播編程+紅警三，python1對1輔導老師。

對於課程模塊，需要：

• 課程表
• 學生課程表：學生和課程的關系表
• 時刻表：課程上課時間設置

由於課程會有多個狀態，這個可以先在constants.py中去記錄好（即添加代碼如下）

COURSE_STATUS = {
    1: "未開始選課",
    2: "開始選課",
    3: "結束選課",
    4: "結課",
    5: "打分完成",
}

COURSE_OPERATION = {
    1: "開始選課",
    2: "結束選課",
    3: "結課",
    4: "給分",
    5: "查看詳情"
}

然后在course/models.py中導入下面會需要的所有庫

from django.db import models
import datetime
from user.models import Student, Teacher
from constants import COURSE_STATUS, COURSE_OPERATION

1 添加課程模型

在course/models.py中添加代碼如下

def current_year():
    # refer: https://stackoverflow.com/questions/49051017/year-field-in-django/49051348
    return datetime.date.today().year

class Course(models.Model):
    credits = [
        (1, 1),
        (2, 2),
        (3, 3),
        (4, 4),
        (5, 5),
    ]
    semesters = [
        ("Autumn", "上"),
        ("Spring", "下")
    ]
    name = models.CharField(max_length=50, verbose_name="課程名")
    introduction = models.CharField(max_length=250, verbose_name="介紹")
    credit = models.IntegerField(verbose_name="學分")
    max_number = models.IntegerField(verbose_name="課程最大人數")

    year = models.IntegerField(verbose_name="年份", default=current_year)
    semester = models.CharField(max_length=20, verbose_name="學期", choices=semesters)

    # 未開始選課， 1
    # 開始選課，未結束選課 2
    # 結束選課， 3
    # 結課 4
    # 已打完分 5
    status = models.IntegerField(verbose_name="課程狀態", default=1)

    teacher = models.ForeignKey(Teacher, verbose_name="課程教師", on_delete=models.CASCADE)

    def get_status_text(self):
        return COURSE_STATUS[self.status]

    def get_op_text(self):
        return COURSE_OPERATION[self.status]

    def get_current_count(self):
        courses = StudentCourse.objects.filter(course=self, with_draw=False)
        return len(courses)

    def get_schedules(self):
        schedules = Schedule.objects.filter(course=self)
        return schedules

    def __str__(self):
        return "%s (%s)" % (self.name, self.teacher.name)

補充說明： get_status_text和get_op_text方法是為了方便在模板中調用。

2 添加課程時刻表模型

在course/models.py中添加代碼如下

def weekday_choices():
    weekday_str = ['周一', '周二', '周三', '周四', '周五', '周六', '周日']
    return [(i+1, weekday_str[i]) for i in range(7)]


class Schedule(models.Model):
    weekday = models.IntegerField(choices=weekday_choices(), verbose_name="日期")
    start_time = models.TimeField(verbose_name="上課時間")
    end_time = models.TimeField(verbose_name="下課時間")
    location = models.CharField(max_length=100, verbose_name="上課地點")
    remarks = models.CharField(max_length=100, verbose_name="備注", null=True, blank = True)

    start_week = models.IntegerField(verbose_name="第幾周開始")
    end_week = models.IntegerField(verbose_name="第幾周結束")

    intervals = [
        (1, "無間隔"),
        (2, "每隔一周上一次")
    ]
    week_interval = models.IntegerField(verbose_name="周間隔", choices=intervals, default=1)

    course = models.ForeignKey(Course, verbose_name="課程名", on_delete=models.CASCADE)

    def __str__(self):
        s = "第%s周-第%s周 " % (self.start_week, self.end_week)
        if self.week_interval == 2:
            s += "隔一周 "
        s += "%s %s-%s " % (self.get_weekday_display(), self.start_time.strftime("%H:%M"),
                            self.end_time.strftime("%H:%M"))
        s += "在%s" % self.location
        if self.remarks:
            s += " %s" % self.remarks
        return s

3 添加學生課程關系表模型

在course/models.py中添加代碼如下

class StudentCourse(models.Model):
    create_time = models.DateTimeField(auto_now=True)
    with_draw = models.BooleanField(default=False)
    with_draw_time = models.DateTimeField(default=None, null=True)

    scores = models.IntegerField(verbose_name="成績", null=True)
    comments = models.CharField(max_length=250, verbose_name="老師評價", null=True)

    rates = [
        (1, 1),
        (2, 2),
        (3, 3),
        (4, 4),
        (5, 5),
    ]

    rating = models.IntegerField(verbose_name="學生評分", choices=rates, null=True, help_text="5分為最滿意，最低分是1分")
    assessment = models.CharField(max_length=250, verbose_name="學生評價", null=True)

    student = models.ForeignKey(Student, on_delete=models.CASCADE)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)

4 建立（更新）數據庫

同第三節第三部分

簡單復述一遍，即在項目文件夾下打開命令行窗口，執行：

python manage.py makemigrations
python manage.py migrate