ORM版學員管理系統 2

時間 2019-11-13

標籤 orm 學員管理系統欄目 Java 简体版

原文原文鏈接

學生信息管理

展現學生信息

URL部分

url(r'^student_list/', app01_views.student_list, name="student_list"),

視圖部分

def student_list(request):
    student_list = models.Student.objects.all()
    return render(request, "student_list.html", {"student_list": student_list})

前端部分

<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="x-ua-compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>學生列表</title>
</head>
<body>
<a href="{% url 'add_student' %}">添加學生</a>
<table border="1">
  <thead>
  <tr>
    <th>#</th>
    <th>id</th>
    <th>學生姓名</th>
    <th>學生班級</th>
    <th>開班日期</th>
    <th>操做</th>
  </tr>
  </thead>
  <tbody>
  {% for student in student_list%}
  <tr>
  <td>{{ forloop.counter}}</td>
  <td>{{ student.id }}</td>
  <td>{{ student.sname }}</td>
  <td>{{ student.cid.cname }}</td>
  <td>{{ student.cid.first_day|date:'Y-m-d' }}</td>
  <td>
    <a href="{% url 'delete_student' student.id %}">刪除</a>
    <a href="{% url 'edit_student' student.id %}">編輯</a>
  </td>
  </tr>
  {% endfor %}
  </tbody>
</table>
</body>
</html>

刪除學生信息

URL部分

url(r'^delete_student/(?P<sid>\d+)$', app01_views.delete_student, name="delete_student"),

視圖部分

def delete_student(request, sid):
    models.Student.objects.filter(id=sid).delete()
    return redirect(reverse("student_list"))

前端部分

<a href="{% url 'delete_student' student.id %}">刪除</a>

添加學生信息

URL部分

url(r'^add_student/$', app01_views.add_student, name="add_student"),

視圖部分

def add_student(request):
    if request.method == "POST":
        sname = request.POST.get("sname")
        class_id = request.POST.get("class_id")
        models.Student.objects.create(sname=sname, cid_id=class_id)
        return redirect(reverse("student_list"))

    class_list = models.Class.objects.all()
    return render(request, "add_student.html", {"class_list": class_list})

前端部分

<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="x-ua-compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>添加學生</title>
</head>
<body>
<form action="{% url 'add_student' %}" method="post">
  {% csrf_token %}
  <p>學生姓名：<input type="text" name="sname"></p>
  <label for="class_id">所在班級：</label>
    <select name="class_id" id="class_id">
      {% for class in class_list %}
        <option value="{{ class.id }}">{{ class.cname }}</option>
      {% endfor %}
    </select>
    <p><input type="submit" value="提交"></p>
</form>
</body>
</html>

編輯學生信息

URL部分

url(r'^edit_student/(?P<sid>\d+)$', app01_views.edit_student, name="edit_student"),

視圖部分

def edit_student(request, sid):
    # 獲取到編輯的學生對象
    student_obj = models.Student.objects.get(id=sid)
    # 獲取全部的班級數據
    class_list = models.Class.objects.all()

    if request.method == "POST":
        sname = request.POST.get("sname")
        class_id = request.POST.get("class_id")
        student_obj.sname = sname
        student_obj.cid_id = class_id
        student_obj.save()
        return redirect(reverse("student_list"))

    return render(request, "edit_student.html", {"student": student_obj, "class_list": class_list})

前端部分

<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="x-ua-compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>編輯學生信息</title>
</head>
<body>
<form action="{% url 'edit_student' student.id %}" method="post">
  {% csrf_token %}
  <p>學生姓名：<input type="text" name="sname" value="{{ student.sname }}"></p>
  <label for="class_id">所在班級：</label>
  <select name="class_id" id="class_id">
    {% for class in class_list %}
      {% if class.id == student.cid_id %}
        <option value="{{ class.id }}" selected>{{ class.cname }}</option>
      {% else %}
        <option value="{{ class.id }}">{{ class.cname }}</option>
      {% endif %}
    {% endfor %}
  </select>
  <p><input type="submit" value="提交"></p>
</form>
</body>
</html>

基於對象的跨表查詢

一對多查詢（班級表和學生表）

正向查詢（由學生表查詢班級表）html

查詢學生的班級信息前端

>>> student_obj = models.Student.objects.first()
>>> student_obj.cid  # 經過model類中的屬性查找到對應的外鍵數據對象
<Class: Class object>
>>> student_obj.cid.cname
'1班'
>>> student_obj.cid_id  # 獲取實際外鍵的值
1

反向查詢（由班級表查詢學生表）app

查詢班級的學生信息oop

>>> class_obj = models.Class.objects.first()  # 獲取第一個班級對象
>>> class_obj.student_set.all()  # 經過表名_set反向查詢出全部的學生
<QuerySet [<Student: Student object>, <Student: Student object>]>

注意：post

若是不在外鍵的字段中設置related_name的話，默認就用表名_set。ui

若是設置了related_name="students"，反向查詢時可直接使用students進行反向查詢。url

>>> class_obj.students.all()

一對一查詢

表結構設計spa

class Student(models.Model):
    sname = models.CharField(max_length=32, verbose_name="學生姓名")
    the_class = models.ForeignKey(to=Class, to_field="id", on_delete=models.CASCADE, related_name="students")
    detail = models.OneToOneField(to="StudentDetail", null=True)


class StudentDetail(models.Model):
    height = models.PositiveIntegerField()
    weight = models.PositiveIntegerField()
    email = models.EmailField()

正向查詢（由學生信息表查詢學生詳情表）設計

>>> student_obj = models.Student.objects.first()
>>> student_obj.detail.email
'1@1.com'

反向查詢（由學生詳情表反向查詢學生信息表）code

>>> detail_obj = models.StudentDetail.objects.get(id=1)
>>> detail_obj.student.sname
'a'

相關標籤/搜索

每日一句

每一个你不满意的现在，都有一个你没有努力的曾经。